In March 2013, a novel avian influenza A H7N9 virus was emerged in China, which cause rapidly progressive pneumonia and with a high fatality rate. Serologic studies to evaluate neutralizing antibodies of infected patients and birds are invaluable tools for immunogenicity research of H7N9 and epidemiological investigation. Conventional neutralization assays are laborious and time-consuming which also hampered by biosafety requirement. In this study, We construct and produce pseudovirus bearing the full-length hemagglutinin (HA) of H7N9 virus in the Env-defective, luciferase-expressing HIV-1 backbone. The production of lentiviral pseudovirus was analysed by HA gene specific real-time reverse-transcription PCR, transmission electron microscopy (TEM), and Western Blot assay to prove the nucleic acid replication, the morphology of virus, and the expression of HA protein in pseudovirus. After that pseudovirus based inhibition assay was established to detect neutralizing antibodies of a panel of serum samples. Our results demonstrated that H7N9 pseudovirus which had single-cycle infection was generated. By comparing the neutralization antibody titers, pseudovirus based neutralization test could be recognized as an alternative of conventional microneutralization (MN). Hence, we conclude that it is possible to use pseudovirus inhibition assay to screen sera samples, as well as evaluate vaccine-induced neutralizing antibodies against H7N9 virus.

A pandemic happens when a novel influenza A virus is able to infect and transmit efficiently to a new, distinct host species. Although the exact timing of pandemics is uncertain, it is known that both viral and host factors play a role in their emergence. Species-specific interactions between the virus and the host cell determine the virus tropism. These include binding and entering cells, replicating the viral RNA genome within the host cell nucleus, assembling, maturing, and releasing the virus to neighbouring cells, tissues, or organs before transmitting it between individuals. Influenza has a vast and antigenically varied reservoir. In wild aquatic birds, the infection is typically asymptomatic. Avian influenza virus (AIV) can cross into new species, and occasionally, it can acquire the ability to transmit from human to human. A pandemic might occur if a new influenza virus acquires enough adaptive mutations to maintain transmission between people. This review highlights the key determinants AIV must achieve to initiate a human pandemic and describes how AIV mutates to establish tropism and stable human adaptation. Understanding the tropism of AIV may be crucial in preventing virus transmission in humans and may help design vaccines, antivirals and therapeutic agents against the virus.

The domestic ducks (Anas platyrhynchos domesticus) are resistant to most of the highly pathogenic avian influenza virus (HPAIV) infections. In this study, we characterized the lung proteome and phosphoproteome of ducks infected with HPAI H5N1 virus (A/duck/India/02CA10/2011/Agartala) at 12 hr, 48 hr and 5 days post infection condition. Total 2082 proteins were differentially expressed and 320 phosphorylation sites mapping to 199 phosphopeptides corresponding to 129 proteins were identified. Functional annotation of proteome data analysis reveals activation of RIG-I-like receptor and Jak-STAT signaling pathways, that lead to induction of interferon stimulated genes (ISGs) expression. The pathway analysis of phosphoproteome datasets also confirms the activation of RIG I, Jak-STAT signaling, NF-kappa B signaling and MAPK signaling pathways in the lung tissues. The induction of ISGs proteins (STAT1, STAT3, STAT5B, STAT6, IFIT5 and PKR) establishes protective antiviral immune response in duck lung tissue. Further, the protein-protein interaction network analysis identified proteins like AKT1, STAT3, JAK2, RAC1, STAT1, PTPN11, RPS27A, NFKB1 and MAPK1 as main hub proteins that might play important roles in disease progression in ducks. Together, functional annotation of proteome and phosphoproteome datasets reveals the molecular basis of the disease progression and disease resistance mechanism in ducks infected with HPAI H5N1 virus.

H9N2 avian influenza viruses have become globally widespread in poultry over the last two decades and represent a genuine threat both to the global poultry industry but also humans through their high rates of zoonotic infection and pandemic potential. H9N2 viruses are generally hyperendemic in effected countries and have been found in poultry in many new regions in recent years. In this review we examine the current global spread of H9N2 avian influenza viruses as well as their host range, tropism, transmission routes and the risk posed by these viruses to human health.

Influenza A viruses (IAV) are widespread viruses affecting avian and mammalian species worldwide. Outbreaks of IAV in poultry are usually associated with substantial morbidity and mortality, significantly affecting the poultry industry and food security. IAVs from avian species can be transmitted to mammals including humans and, thus, they are of inherent pandemic concern. Most of the efforts to understand the pathogenicity and transmission of avian origin IAVs have been focused on H5 and H7 subtypes due to their highly pathogenic phenotype in poultry. However, IAV of the H9 subtype that circulate endemically in poultry flocks in some regions of the world have also been associated with cases of zoonotic infections. As a result, the World Health Organization includes avian origin H9N2 IAV among the top in the list of IAVs of pandemic concern. In this review, we discuss the interspecies transmission of H9N2 between avian and mammalian species and the molecular factors that are thought relevant for this spillover. Additionally, we discuss factors that have been associated with the ability of these viruses to transmit through the respiratory route in mammalian species.

2014 marked the first emergence of avian influenza A(H5N8) in Jeonbuk Province, South Korea, which then quickly spread worldwide. In the midst of the 2020-21 H5N8 outbreak, it spread to domestic poultry and wild waterfowl shorebirds, leading to the first human infection in Astrakhan Oblast, Russia. Despite being clinically asymptomatic and without direct human-to-human transmission, the World Health Organisation stressed the need for continued risk assessment given the nature of Influenza to reassort and generate novel strains. Given its promiscuity and spread to humans, the urgency to understand the mechanisms of possible species jumping to avert disastrous pandemics is increasing. Addressing the epidemiology of H5N8 and its mechanisms of species jumping and its implications, mutational and reassortment libraries can potentially be built, allowing them to be tested on various models complemented with deep-sequencing and automation. With the knowledge on mutational patterns, cellular pathways, drug resistance mechanisms and effects of host proteins can allow better preparedness against H5N8 and other influenza A viruses.

Avian influenza viruses (AIVs) are highly contagious respiratory viruses of birds, lead-ing to significant morbidity and mortality globally and causing substantial economic losses to the poultry industry. Since their first isolation in 2013, the Asian-origin H5N1 highly pathogenic avian influenza viruses (HPAI) of clade 2.3.4.4b have undergone unprecedented evolution and re-assortment of internal gene segments and have spread to Asia, Europe, Africa, and America, caus-ing outbreaks in all the poultry categories. Novel epidemiological and pathobiological character-istics, distinct from other clades, are specific of clade 2.3.4.4b viruses. Wild waterfowl, the natu-ral reservoir of AIVs, are frequently found infected with clade 2.3.4.4b viruses, which can also cause high morbidity and mortality in these birds. The sustained clade 2.3.4.4b virus circulation in waterfowl has also led to virus infection in other wild bird species, with implications for the conservation of endangered species. Furthermore, clade 2.3.4.4b viruses have been isolated in var-ious wild and domestic mammals worldwide, and critical mutations related to virus adaptation to mammalian species have been identified, raising concerns about virus spillover to humans. The main clinical signs, and anatomopathological findings associated to clade 2.3.4.4b virus infection in birds and non-human mammals are hereby summarized.

As exemplified by the global response to the SARS-CoV-2 pandemic, whole genome sequencing played an important role in monitoring the evolution of novel viral variants and provided guidance on potential antiviral treatments. The recent rapid and extensive introduction and spread of highly pathogenic avian influenza virus in Europe, North America and elsewhere raises the need for similarly rapid sequencing to aid in appropriate response and mitigation activities. To facilitate this objective, we investigated a next generation sequencing platform that uses a portable nanopore sequencing device to generate and present data in real time. This platform offers the potential to extend in-house sequencing capacities to laboratories that may otherwise lack resources to adopt sequencing technologies requiring large benchtop instruments. We evaluated this platform for routine use in a diagnostic laboratory. In this study we evaluated different primer sets for the whole genome amplification of influenza A virus and evaluated five different library preparation approaches for sequencing on the nanopore platform using the MinION flow-cell. A limited amplification procedure and a rapid procedure were found to be best among the approaches taken.

The H7 subtype of avian influenza viruses (AIV) stands out among other AIV. The H7 viruses cir-culate in ducks, poultry, equine and have repeatedly caused outbreaks of disease in humans. In or-der to study the pathogenicity factors of H7N1 viruses, several variants were obtained, starting with laboratory strain, with a history of 12 passages through chicken embryos. This strain, A/chicken/Rostock/R0p/1934(H7N1) (R0p) had only 3 substitution in HA relatively A/Chicken/Rostock/45/34(H7N1), substitution Arg140Gly among them. 10 variants of this strain was obtained and studied to ascertain its biological property, genome stability and factors of patho-genicity. Strain R0p had decreased virulence for chicken, comparing with described in literature virulence of A/FPV Rostock/34 and A/chicken/Rostock/34 viruses. After 10 passages through the chicken lungs variant was obtained much more pathogenic than the starting R0p. The study of in-termediate passages through the chicken lungs showed that the jump in pathogenicity had occurred sharply between the fifth and sixth passage. By cloning these variants, a pair of strains (R5p and R6p) were obtained, and the complete genomes of these strains were sequenced. Single amino acid substitution was revealed, namely reversion Gly140Arg in HA1. This amino acid is located at the head part of the hemagglutinin, adjacent to the receptor-binding site. In addition to the increased pathogenicity for chicken and mice, R6p differs from R5p in the pattern of foci in cell culture and an increased affinity for a negatively charged receptor analogue, while maintaining a pattern of recep-tor binding specificity and the pH optimum of the HA conformational change.

We investigate the possible laboratory origins of the highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b genotype B3.13, currently affecting various animal species and causing sporadic human infections. The first detection of HPAI H5N1 clade 2.3.4.4b in the Netherlands in 2020 raises concerns about earlier gain-of-function research. The proximal origins of HPAI H5N1 Clade 2.3.4.4b may be the USDA Southeast Poultry Research Laboratory (SEPRL) in Athens, Georgia and the Erasmus Medical Center in Rotterdam, the Netherlands. Genetic analysis indicates that genotype B3.13 emerged in 2024 and exhibits genetic links to genotype B1.2, which was identified to have originated in Georgia in January 2022 after the start of serial passage research with H5Nx clade 2.3.4.4 in mallard ducks at the USDA Southeast Poultry Research Laboratory (SEPRL) in Athens, Georgia in April 2021. Genotype B1.2 was found in a bottlenose dolphin (Tursiops truncatus) in March 2022 in Florida, indicating sudden new adaptations to different animal species. The NP gene of H5N1 clade 2.3.4.4b (genotype B3.13), which is causing outbreaks in cattle, was reported to have likely originated from an avian influenza A virus derived from mallard ducks. Significant mutations found in recent human cases, including PB2 E627K and PB2 M631L, also suggest links to serial passage experiments. However, further investigation is urgently needed to confirm these findings and to identify all H5N1 laboratory leaks that may have occurred with a focus on mallard ducks and other migratory waterfowl, which have the potential to infect a large number of poultry and livestock facilities around the world. A moratorium on gain-of-function research including serial passage of H5N1 is indicated to prevent a man-made influenza pandemic affecting animals and humans.

Avian Influenza viruses (AIVs) has posed a significant pandemic threat since their discovery. This review mainly focuses on the epidemiology, virology, and pathogenesis, and treatments of avian influenza viruses. We delve into the global spread, past pandemics, clinical symptoms, severity, and immune response related to AIVs. The review also discusses various control measures, including antiviral drugs, vaccines, and potential future directions in influenza treatment and prevention. Lastly, by summarizing the insights from the previous pandemic control, this review aims to direct effective strategies for managing future influenza pandemics.

The H7 subtype of avian influenza viruses (AIV) stands out among other AIV. H7 viruses circulate in ducks, poultry, equine and have repeatedly caused outbreaks of disease in humans. In order to study the pathogenicity factors of H7N1 viruses, several laboratory variants of the A/FPV/Rostock/34 (H7N1) strain were obtained by passages in the chicken lungs. After 10 such passages, a variant was obtained that differed from the parent virus by amino acid substitutions Val109Phe in PB2, Gln621Lys in PB1, Thr32Ala and Leu586Phe in PA Gly140Arg in HA1 and Ala101Thr in HA2 (numbering by H3), Ser82Arg in M2, Arg118Lys and Met124Arg in NS1. No differences were found in proteins NA, NP, M1 and NS2. The resulting variant was hundreds of times more pathogenic for chickens than the original laboratory variant of the virus. The study of intermediate passages showed that the jump in pathogenicity occurs sharply between the fifth and sixth passage through the chicken lungs. By cloning these variants, a pair of strains (R5p and R6p) were obtained, and the complete genomes of these strains were sequenced. Single amino acid substitution was revealed, namely Gly140Arg in HA1. It is important to emphasize that this substitution is a reversion, since Arg is located in position 140 HA1 of original the A/FPV/Rostock/34 (H7N1) virus (GenBank). This amino acid is located at the head part of the hemagglutinin, adjacent to the receptor-binding site. In addition to the increased pathogenicity, R6p differs from R5p by an increased affinity for a negatively charged receptor analogue, an increased affinity for MDCK cells, while maintaining a receptor specificity profile.

In 2021, amidst the COVID-19 pandemic and global food insecurity, the Nigerian poultry sector was yet exposed to highly pathogenic avian influenza (HPAI) virus and its economic challenges. Between 2021 and 2022, HPAI caused 467 outbreaks reported in 31 of the 37 administrative regions in Nigeria. In this study, we characterized the genome of 97 influenza A viruses of the subtypes H5N1, H5N2 and H5N8 identified in different agro-ecological zones and farms during the 2021-2022 epidemic. The phylogenetic analysis of the HA genes showed widespread distribution of the H5Nx clade 2.3.4.4b and similarity with the HPAI H5Nx viruses detected in Europe since late 2020. Topology of the phylogenetic trees indicates the occurrence of several independent introductions of the virus into the country followed by a regional evolution of the virus most probably linked to its persistent circulation in West African territories. An additional evidence of the evolutionary potential of HPAI viruses circulating in this region is the identification in this study of a putative H5N1/H9N2 reassortant virus in a mixed-species commercial poultry farm. Our data confirm Nigeria as a crucial hotspot for HPAI virus introduction from the Eurasian territories and reveal a dynamic pattern of avian influenza virus evolution within the Nigerian poultry population.

In this study, we report the first outbreak of highly pathogenic avian influenza (HPAI) A H5N8, clade 2.3.4.4b in Kosovo on May 19, 2021. The outbreak consisted of three temporal phases: May–June 2021, September–November 2021, and January–May 2022. In total, 32 backyard and 10 commercial holdings tested positive for the virus, affecting 179,198 poultry. Interestingly, the third and last phase of the outbreak coincided with the massive H5N1 clade 2.3.4.4b epidemic in Europe. Phylogenetic analyses of 28 viral strains from Kosovo revealed that they were closely related to the H5N8 clade 2.3.4.4.b viruses that have been circulating in Albania, Bulgaria, Croatia, Hungary, and Russia in early 2021. Whole genome sequencing of the 25 and partial sequencing of 3 H5N8 viruses from Kosovo showed high nucleotide identity, forming a distinctive cluster and suggesting a single introduction. The results of the network analysis were in accordance with the three epidemic waves and suggested that the viral diffusion could have been caused by secondary spreads among farms and/or different introductions of the same virus from wild birds. The persistent circulation of the same virus over a one-year period highlights the potential risk of the virus becoming endemic, especially in settings with non-adequate biosecurity.

Initial attempts to develop monoclonal antibodies as therapeutics to resolve influenza infections focused mainly on searching for antibodies with the potential to neutralise the virus in vitro with classical haemagglutination inhibition and micro-neutralisation assays. This led to the identification of many antibodies that bind to the head domain of haemagglutinin (HA) which generally have potent neutralisation capabilities that block viral entry or viral membrane fusion. However, this class of antibodies has a narrow breadth of protection in that they are usually strain specific. This led to the emphasis on stalk targeting antibodies which are able to bind a broad range of viral targets that span across different influenza subtypes. Recently, a third class of antibodies targeting the vestigial esterase (VE) domain have been characterised. In this review, we describe the key features of neutralising VE targeting antibodies and compare them with head and stalk class antibodies.

A brief overview of the past and present trajectories made by the A(H5N1) avian influenza virus among domestic birds, avian and mammalian wildlife species and humans is presented here, thereby taking into special account the 2.3.4.4b clade of the virus recently emerged in several geographic areas of the globe.

Human infections caused by the H5 highly pathogenic avian influenza virus (HPAIV) sporadically threaten public health. The susceptibility of HPAIVs to baloxavir acid (BXA), a new class of inhibitors for the influenza virus cap-dependent endonuclease, has been confirmed in vitro, but it has not yet been fully characterized. Here, the efficacy of BXA against HPAIVs, including recent H5N8 variants, was assessed in vitro. The antiviral efficacy of baloxavir marboxil (BXM) in H5N1 virus-infected mice was also investigated. BXA exhibited similar in vitro activities against H5N1, H5N6, and H5N8 variants tested in comparison with seasonal and other zoonotic strains. Compared with oseltamivir phosphate (OSP), BXM monotherapy in mice infected with the H5N1 HPAIV clinical isolate, the A/Hong Kong/483/1997 strain, also caused a significant reduction in viral titers in the lungs, brains, and kidneys, thereby preventing acute lung inflammation and reducing mortality. Furthermore, compared with BXM or OSP monotherapy, combination treatments with BXM and OSP using a 48-hour delayed treatment model showed a more potent effect on viral replication in the organs, accompanied by improved survival. In conclusion, BXM has a potent antiviral efficacy against H5 HPAIV infections.

The Influenza A Virus (IAV) represents an enveloped, positive-sense and single-stranded RNA-based virus that infects mammals mainly via the respiratory system, although other bodily systems are also infected and undergo various extents of inflammatory pathogenesis. There are two well-known strains of IAV that cause life-threatening disease in mammals; H1N1 and H5N1, and the first strain caused the 1918 IAV H1N1 pandemic that claimed between 30 and 50 million human lives. Due to the significant ability of IAV to evade important immune recognition, the virus was observed to favor the onset of secondary microbial infections (i.e. bacterial or fungal), as the overall performance of the immune system became transiently weakened during the viral infection. During the IAV H1N1 pandemic, many patients died as a result of bacterial pneumonia, as pathogenic bacteria, such as Streptococcus pneumoniae and Haemophilus influenzae, gained a wider opportunity to colonize and infect vital areas of the lower respiratory tract, and such a phenomenon led to the excessive, prophylactic usage of antibiotics due to the increased levels of panic, which in turn favored the natural selection of bacteria with genes that became resistant to such antibiotics. Antibiotics might be required for usage solely when bacteria are known to be colonizing vital areas of the human body, and this aspect is tricky, as colonization is asymptomatic and screening is consequently rare. Recently, new variants of the avian IAV H5N1 strain were transmitted from live, infected birds to mammals, including humans in some isolated cases, and given that there have already been several zoonotic spillover events overall since the beginning of 2023, we are rapidly approaching the time when a zoonotic spillover into humans will mark the first epidemic outbreak of the avian flu in humans. A lethality rate of 60% was projected by the World Health Organization, as the virus was shown to favor the development of life-threatening hyper-inflammatory responses at the levels of alveolar tissues constituted by Type II pneumocytes. There are hints that novel variants of H5N1 are capable of infecting the intestinal layer, as recently, two dolphins died as a result of ingesting infected birds within the area of the British Isles. IAV is known to suppress the production and transmission of Type I Interferons by expressing various non-structural proteins (NSPs), such as NSP1, which was found to be also packaged into exosomes and transmitted to neighboring uninfected cells, thereby preventing them from responding to the virus in the first place. Additionally, it was determined that NSP1 induces the apoptosis of the cells it is produced in and the neighbouring ones it enters via induced paracrine signalling, and such an aspect may only emphasise upon the critical role that early innate immune stimulation plays in preventing the development of severe respiratory illness afterward, given the context of increased viral ability of suppressing the production of first-line and second-line signals. A more pronounced rate of innate immune evasion would probably be observed in H5N1 IAV infection than in the infection caused by recent variants of H1N1 IAV. The H5N1 strain of IAV was also found to secrete a higher concentration of NSP1 than SARS-CoV-2, indicating the existence of an association to the greater mortality rate of H5N1 IAV infection. A direct, prophylactic stimulation of the interferon system using a reduced oral or nasal dosage of recombinant anti-inflammatory and anti-viral interferon glycoproteins may represent the most viable approach to prevent an emergence of a life-threatening H5N1 IAV pandemic. A similar non-invasive approach could be developed for an Marburg Virus (MARV) and a Nipah Virus (NiV) infection of humans, as risks of the emergence of a Marburg epidemic and also of a Nipah epidemic may be substantial at this stage as well. Clinical testing of clinical approaches as such could be of critical importance at the moment. Animals could also benefit from related clinical approaches. Somatic natural and adaptive lymphocytes treated with IFN I and III could also constitute a substantial approach of immunization and heavily favor an indefinite shift in the evolutionary battle between the host organism and microbes of public health concern, as IFN I and III could improve the immunity of T-lymphocytes against HIV infection and even improve the performance of the mentioned types of immune cells during other types of infections. Likewise, a combination of all intellectual and clinical efforts implicating a shift of scientific and medical focus toward natural immunity in vaccine-related research could be a wise method in making the best efforts to prevent or alleviate the effects of a possible future pandemic, given the highly significant and diverse abilities of microbial “intelligence” to effectively hijack the natural immune system, many times causing severe implications upon the quality of the overall immune response against such microbes.

We investigated the effect of C. psittaci and H9N2 coinfection on HD11 cells in vitro, expecting to find the potential pathogenesis of airsacculitis caused by co-infection of C. psittaci and H9N2. HD11 cells were infected with C. psittaci and/or H9N2 in a different order, and effects of the co-infection on iNOS expression and activity, NO synthesis, cell phagocytosis, and cytokines levels in HD11 cells were determined. Results showed that C. psittaci and H9N2 can significantly aggravate the mortality of HD11 cells compared to the effects of infection with one pathogen alone. In addition, infection with C. psittaci can increase the replication of H9N2 in HD11 cells, whereas decrease the iNOS level and enzyme activity as well as NO concentration of HD11 cells by H9N2 infection. We also found that C. psittaci infection alone can significantly decrease the phagocytosis of HD11 cells, compared to H9N2 infection alone. Furthermore, infection with C. psittaci can increase the mRNA expressions of type Th2 cytokines IL-6 and IL-10 of HD11 cells by H9N2 infection. All the above data indicated that primary C. psittaci infection is able to aggravate H9N2 invasion by down-regulating functions of HD11 cells

During autumn/winter in 2016 – 2017 and 2020 – 2021, highly pathogenic avian influenza viruses (HPAIV) caused severe outbreaks in Germany and Europe. Multiple clade 2.3.4.4b H5 HPAI subtypes were responsible for increased mortality in wild birds and high mortality and massive losses in the poultry sector. To clarify putative entry sources and delineate interconnections between outbreaks in poultry holdings and wild birds, we applied whole-genome sequencing and phylodynamic analyses combined with the results of epidemiological outbreak investigations. Varying outbreak dynamics of the distinct reassortants allowed for the identification of individual, putatively wild bird-mediated entries into backyard holdings, several clusters comprising poultry holdings, local virus circulation for several weeks, direct farm-to-farm transmission and potential reassortment within a turkey holding with subsequent spill-over of the novel reassorted virus into the wild bird population. Whole-genome sequencing allowed for allowed for a unique high-resolution molecular epidemiology analysis of HPAIV H5Nx outbreaks, recommended to be used as a standard tool. The presented detailed account of the genetic, temporal and geographical characteristics of the recent German HPAI H5Nx situation emphasizes the role of poultry holdings as an important source of novel genetic variants and reassortants.

We isolated two highly pathogenic avian influenza viruses (HPAIVs) of subtype H5N8 clade 2.3.4.4b from falcated duck (Anas falcata) feces and environmental water collected at an overwintering site in Japan. Our isolates were almost genetically identical to each other and showed high genetic similarity with H5N8 HPAIVs recently isolated in South Korea, a distant part of Japan, and European countries. These results suggest the potential role of falcated ducks in the dissemination of HPAIVs.

There are four types of influenza viruses: A, B, C, and D. Cattle are susceptible to influenza D infection and serve as a reservoir for this seven-segmented influenza virus. It is generally thought that bovines are not a host of other types of influenza viruses including type A. This long-standing viewpoint has been challenged by the recent highly pathogenic avian influenza (HPAI) H5N1 outbreaks in dairy cows in the United States. To date, HPAI H5N1 has spread into nine states affecting 49 dairy herds and causing clinical symptoms including reduced appetite, fever, and a sudden drop in milk production. This review article describes the current epidemiological landscape of HPAI H5N1 in U.S. dairy cows and the recent interspecies transmission events of HPAI H5N1 in other mammals reported in other countries. The review also discusses adaptation mutations of HPAI H5N1 to mammalian hosts and vaccination strategies. Finally, it summarizes some immediate questions that need to be addressed towards a better understanding of infection biology, transmission, and immune response of HPAI H5N1 in bovines.

Over the last decade, highly pathogenic avian influenza (HPAI) has severely affected poultry production systems across the globe. In particular, massive pre-emptive depopulation of all poultry within the certain distance has raised concerns regarding animal welfare and food security. Thus, alternative approaches to reducing unnecessary depopulation, such as risk-based depopulation, are highly demanded. This paper proposes a data-driven method to generate a rule table and risk score for each farm to identify preventive measures against HPAI. To evaluate the proposed method, 105 cases of HPAI occurring in a total of 381 farms in Jeollanam-do from 2014 to 2023 were evaluated. The accuracy of preventive measure identification was assessed for each case using both the conventional culling method and the proposed data-driven method. The evaluation showed that the proposed method achieved an accuracy of 84.19%, significantly surpassing the previous 10.37%. The result was attributed to the proposed method reducing the false-positive rate by 83.61% compared with the conventional method, thereby enhancing the reliability of identification. The proposed method is expected to be utilized in selecting farms for monitoring and management of HPAI.

High pathogenicity avian influenza (HPAI) H5N1 clade 2.3.4.4b continues to have a substantial impact on wildlife, globally. A recent study has described the putative detection of HPAI in clinically healthy penguins, and those which were fitted with satellite tags reportedly engaged in apparently normal foraging behaviour in the months following sample collection. Herein we investigate the diagnostic approach utilised, and reveal that while the authors likely did detect subtype H5 influenza A virus, the most parsimonious conclusion is that they detected low pathogenicity H5 rather than HPAI H5N1. In response, we have provided an overview key considerations when selecting a diagnostic and outline published diagnostic assays that should be considered for future studies.

In 2020-2021, the second massive dissemination of a highly-pathogenic avian influenza (HPAI) of H5Nx subtype occurred in Europe. During this period, the virus caused numerous outbreaks in poultry, including in the Czech Republic. In the present study, we provide an insight into the genetic variability of the Czech/2021 (CZE/2021) H5N8 viruses to determine the relationships between strains from wild and domestic poultry and to infer transmission routes between the affected flocks of commercial poultry. For this purpose, whole genome sequencing and phylogenetic analysis of 70 H5N8 HPAI genomes representing 79.7% of the cases were performed. All CZE/2021 H5N8 viruses belonged to the 2.3.4.4b H5 lineage and circulated without reassortment, retaining the A/chicken/Iraq/1/2020 H5N8-like genotype constellation. Phylogenetic analysis suggested frequent local transmission of H5N8 HPAI from wild birds to minor poultry and extensive farm-to-farm spread among commercial poultry farms. In addition, the analysis suggested one cross-border transmission event. Indirect transmission via contaminated materials was considered the most likely source of infection. Improved biosecurity and increased collaboration between the field veterinarians and the laboratory are essential to limit the local spread of the virus and to reveal and interrupt critical routes of infection.

The GLUT members belong to a family of glucose transporter proteins that facilitate glucose transport across the cell membrane. The mammalian GLUT family consists of thirteen members (GLUTs 1-12 and HMIT). Humans have a recently duplicated GLUT member, GLUT14. Avians express the majority of GLUT members. The arrangement of multiple GLUTs across all somatic tissues signifies the important role of glucose across all organisms. Defects in glucose transport have been linked to metabolic disorders, insulin resistance and diabetes. Despite the essential importance of these transporters, our knowledge regarding GLUT members in avians is fragmented. It has been clear that there are no chicken orthologs of mammalian GLUT4 and GLUT7. Our examination of GLUT members in the chicken revealed that some chicken GLUT members do not have corresponding orthologs in mammals. We review the information regarding GLUT orthologs and their function and expression in mammals and birds, with emphasis on chickens and humans.

Background: Annual influenza epidemics are a serious public health problem, causing particularly severe morbidity and mortality in high-risk groups. The study aimed to understand Poles' attitudes and beliefs towards influenza vaccinations in the flu season of 2022–2023, analyze preferences and unmet needs regarding influenza vaccinations, and examine the perception and acceptance of the influenza vaccine among individuals at risk of flu complications. Methods: A cross-sectional survey-based study was carried out on a sample of 1446 respondents. The Google Forms questionnaire was created and disseminated electronically using social media and e-mail. The pre-test was performed at the beginning of the project. Results: The majority of respondents (71%) could identify "high-risk groups" recommended for influenza vaccination. Furthermore, it was observed that individuals aged 21 to 59 demonstrated a higher level of knowledge in this regard compared to those below 20 and above 65 years old, and individuals with higher and medium education levels were much better at identifying risk groups for influenza virus infection. The majority of respondents (52.01%) reported receiving influenza vaccination at some point in the past, with 32.12% receiving it in the 2022–2023 flu season and 41.09% in the 2021–2022 season. The majority of respondents declaring acceptance of the vaccine for the 2022-2023 season were in the high-risk group. Only 17.28% of respondents declared receiving both influenza and SARS-CoV-2 vaccines in the 2022-2023 season, with the vast majority being respondents from the "high-risk group" (p

Despite the importance of influenza vaccination for healthcare workers (HCWs), their uptake remains challenging. This study aimed to measure influenza vaccine hesitancy among HCWs in Nakhon Phanom province, Thailand. A representative cross-sectional survey was conducted at six hospitals during August – September 2020 using a self-administered questionnaire. HCWs delaying getting influenza vaccines, accepting but unsure, or refusing with doubts were categorized as hesitant. Those accepting without any doubts were classified as non-hesitant. Vaccine hesitancy determinants were identified by multivariable logistic regression analysis. A total of 338 participants (97%) completed the questionnaires; most were female nurses working at district hospitals without pre-existing chronic medical conditions. Nearly 60% of participants (197/338) exhibited influenza vaccine hesitancy, and significant factors included age above 50 years adjusted odds ratio [aOR] 3.2, 95% CI 1.3-8.5), fair knowledge of influenza/vaccination (aOR 0.4, 95% CI 0.2-0.8), and negative influence of other HCW (High level– aOR 2.3, 95% CI 1.1-4.8; Moderate level- aOR 2.1, 95% CI 1.1-4.4). Imparting updated information to the HCW combined with positive guidance from influential peers may help reduce this hesitancy.

In 2021/2022, the re-emergence of highly pathogenic avian influenza (HPAI) occurred in Europe. The outbreak was seeded from two sources, resident and reintroduced viruses, which is unprecedented in the recorded history of avian influenza. The dominating subtype was H5N1, representing a reversion to the original A/goose/Guangdong/1/1996-like subtype combination. In this study, we present a whole genome sequence and a phylogenetic analysis of 57 H5N1 HPAI and two low pathogenic avian influenza (LPAI) H5N1 strains collected in the Czech Republic during 2021/2022. Phylogenetic analysis revealed close relationships between H5N1 genomes from poultry and wild birds and secondary transmission in commercial geese. The genotyping showed considerable genetic heterogeneity among Czech H5N1 viruses with six different HPAI genotypes, three of which were apparently unique. In addition, second-order reassortment relationships were observed with the direct involvement of co-circulating H5N1 LPAI strains. The genetic distance between Czech H5N1 HPAI and the closest LPAI segments available in the database illustrates the profound gaps in our knowledge of circulating LPAI strains. The changing dynamics of HPAI in the wild may increase the likelihood of future HPAI outbreaks and present new challenges in poultry management, biosecurity, and surveillance.

In spite of prevalence gaps in several micronutrients supporting immune function, significance of their deficits/supplementation for efficacy of vaccines is underinvestigated. Thus, influence of supplementation combining vitamins C and D, zinc, selenium and manganese, and N-acetyl-cysteine on mouse IgG responses and underlying mechanisms to seasonal quadrivalent influenza vaccine (QIV) was investigated. QIV was given in two doses (28 days apart). The supplementation starting 5 days before the first injection increased the total serum IgG titre, through stimulation of germinal centre (GC) reaction in secondary lymphoid organs (SLOs), as indicated by increase in the frequency of GC B cells and follicular CD4+ T helper (Th) cells, and IL-21-producing Th cells. Additionally, the supplementation “optimized” IgG response following the second QIV injection by supporting more favorable (in respect to virus clearance) IgG2a response through favoring Th1 differentiation as indicating by Th1 (INF-γ) /Th2 (IL-4) signature cytokine level ratio upon QIV restimulation in SLO cell cultures. This most likely reflected partly their antioxidant action (as indicated by redox status analyses) on Th cell differentiation. Thus, the study forms solid base for further research aimed at repurposing use this safe and inexpensive micronutrient combination as an adjuvant for virus influenza vaccine.

The emergence of the H3N2 influenza virus in 1968 marked a significant event as it crossed the species barrier. Since then, ongoing mutational dynamics have led to the formation of antigenic clusters, prompting the World Health Organization to advocate for regular updates to H3N2 vaccines. Research in the Western Pacific region underscores the necessity for heightened awareness and effective control strategies. Stemming from avian influenza A, the 1968 H3N2 influenza pandemic resulted in the deaths of one million people globally, with its seasonal variants primarily affecting older individuals and causing severe illness due to antigenic drift. To address the challenge of vaccine efficacy against H3N2 mutations, researchers are exploring innovative strategies such as precise antigenic material administration, controlled release patterns, understanding immune system mechanisms, and glycan engineering. This review comprehensively examines various aspects of the Influenza A (H3N2) virus, encompassing its virological characteristics, evolutionary trends, global epidemiology, vaccination strategies, antiviral interventions, and emerging diagnostic approaches. It underscores the impact of antigenic variation on vaccine design and effectiveness, seasonal outbreak patterns, pandemic potential, and the interplay between viral factors and host immune responses. Moreover, the review evaluates antiviral therapies and the issue of drug resistance, emphasising the necessity for multidisciplinary approaches involving researchers, healthcare professionals, and policymakers to comprehend H3N2 and enhance public health interventions.

Epidemic diseases that arise from infectious RNA viruses, particularly influenza viruses, pose a constant threat to the global economy and public health. Viral evolution has undermined the efficacy of acquired immunity from vaccines and the antiviral effects of FDA-approved drugs. As such, there is an urgent need to develop new antiviral lead agents. Natural compounds, owing to their historical validation of application and safety, have become a promising solution. In this light, a novel marine bacterium, Pseudomonas sp. M20A4R8, has been found to exhibit significant antiviral activity [half maximal inhibitory concentration (IC50) = 1.3 µg/mL, selectivity index (SI) = 919.4] against influenza virus A/Puerto Rico/8/34, surpassing the activity of chloroquine. The antiviral response by M20A4R8 extract was induced during post-entry stages of the influenza virus, indicating suitability for post-application after the establishment of viral infection. Furthermore, post-treatment with M20A4R8 extract protected the host from virus-induced apoptosis, suggesting its potential use in acute respiratory disease complexes resulting from immune effectors' overstimulation and autophagy-mediated self-apoptosis. The extract demonstrated an outstanding therapeutic index against influenza virus A/Wisconsin/15/2009 (IC50 = 8.1 µg/mL, SI = 146.2) and B/Florida/78/2015 Victoria lineage (IC50 = 3.5 µg/mL, SI = 343.8), indicating a broad anti-influenza virus activity with guaranteed safety and effectiveness. This study provides a new perspective on mechanisms for preventing a broad spectrum of viral infections through antiviral agents from novel and natural origins. Future studies on a single or combined compound from the extract hold promise, encouraging its use in preclinical challenge tests with various influenza virus strains.

A number of studies suggested that influenza vaccination can provide protection against COVID-19 but the underlying mechanisms that could explain this association is still unclear. In this study, the effect of the 2021/2022 seasonal influenza vaccination on the immune response to the booster dose of anti-SARS-CoV-2 vaccination was evaluated in a cohort of healthy individuals. One hundred and thirteen participants were enrolled, and 74 of them with no prior COVID-19 diagnosis or significant co-morbidities were considered for the analysis. Participants received the anti-influenza tetravalent vaccine and the booster dose of the anti-SARS-CoV-2 vaccine or the anti-SARS-CoV-2 vaccine alone. Blood was collected before and 4 weeks after each vaccination and 12 weeks after SARSCoV2 vaccination and analyzed for anti-flu and anti-spike-specific antibody titers and for in vitro influenza and SARS-CoV-2 neutralization capacity. Results indicated an increased reactivity in subjects who received both influenza and SARSCoV2 vaccinations, as compared to those who received only the SARS-CoV-2 vaccine, with sustained anti-spike antibody titers up to 12 weeks post-vaccination. Immune response to influenza vaccine was evaluated and individuals were stratified as high or low responders. High responders showed increased antibody titers against SARSCoV2 vaccine both after 4- and 12-weeks post-vaccination. On the contrary, the individuals classified as low responders were less responsive to the SARS-CoV-2 vaccine. These data indicate that both external stimuli, such as influenza vaccination, and the host's intrinsic ability to respond to stimuli play a role in the response to vaccine.

Highly pathogenic (HP) avian influenza viruses (AIVs) are naturally restricted to H5 and H7 subtypes with a polybasic cleavage site (CS) in the hemagglutinin (HA) and any AIV with an intravenous pathogenicity index (IVPI) ≥1.2. Only few non-H5/H7 viruses fulfill the criteria of HPAIVs; nevertheless, it remains unknown why these viruses did not spread in domestic birds. In 2012, a unique H4N2 virus with a polybasic CS 322PEKRRTR/G329 was isolated from quails in California which, however, was avirulent in chickens. This is the only known non-H5/H7 virus with four basic amino acids in the HACS. Here, we investigated the virulence of this virus in chickens after expansion of the polybasic CS by substitution of T327R (322PEKRRRR/G329) or T327K (322PEKRRKR/G329) with or without reassortment with HPAIVs H5N1 and H7N7. The impact of single mutations or reassortment on virus fitness in vitro and in vivo was studied. Efficient cell culture replication of T327R/K carrying H4N2 viruses increased by trypsin, particularly in MDCK cells, and reassortment with HPAIV H5N1. Likewise, replication, virus excretion and bird-to-bird transmission of H4N2 was remarkably compromised by the CS mutations, but restored after reassortment with HPAIV H5N1, although not with HPAIV H7N7. Viruses carrying the H4-HA with or without R327 or K327 mutations and the other gene segments from HPAIV H5N1 exhibited high virulence and efficient transmission in chickens. Together, increasing the number of basic amino acids in the H4N2 HACS was detrimental for viral fitness particularly in vivo but compensated by reassortment with HPAIV H5N1. This may explain the absence of non-H5/H7 HPAIVs in poultry.

An influenza A virus (H3N2) with an envelope with the same structure as COVID-19 was used for antiviral testing of material surfaces, in comparison with some results of feline calicivirus. The evaluation method used was the film adhesion method, in which the virus solution is placed on the material and adhered to it using a film. The evaluation method was based on the film adhesion method, in which the virus solution is placed on the material and adhered with a film, and the plaque method, in which the cell virus is allowed to infect the material and form plaques, but the appropriate virus concentration must be adjusted to observe the plaques. When not under that restriction, the plaques are often incomplete; this is observed. For this reason, this study applied an area measurement method that can reflect viral activity even when plaques are not obtained. This study revealed that different types of metallic materials have different antiviral properties. Specifically, the antiviral activity of iron, carbon steel, and nickel was relatively high, while that of stainless steel and titanium was relatively low. The order of antiviral activity was as follows: Fe, SS400, Ni, SUS316L, SUS304, and Ti.

Metabolomics is a powerful set of methods that uses analytical techniques to identify and quantify metabolites in biological samples, providing a snapshot of the metabolic state of a biological system. In medicine, metabolomics can help diagnose diseases, reveal molecular basis of a disease, and monitor treatment responses, while in agriculture, it can improve crop yields and plant breeding. However, animal metabolomics faces several challenges due to the complexity and diversity of animal metabolomes, the lack of standardized protocols, and the difficulty in interpreting metabolomic data. The current dataset includes quantitative metabolomic profiles of eye lens tissues from 26 bird species (111 specimens) that can aid researchers in developing new experiments, mathematical models, and integrations with other omics data. The dataset includes raw 1H NMR spectra, protocols for sample preparation, and data preprocessing with the final table containing information on 89 reliably identified and quantified metabolites. The dataset is quantitative, making it relevant for supplementing with new specimens or comparison groups, followed by data mining and expected new interpretations. It was obtained from bird specimens collected in compliance with ethical standards and reveals potential differences in metabolic pathways due to phylogenetic difference or environmental exposure.

The human antibody response to influenza virus infection or vaccination is as complicated as it is essential for protection against flu. The constant antigenic changes of the virus to escape human herd immunity hinder the yearly selection of vaccine strains since it is hard to predict which virus strains will circulate for the coming flu season. A "universal" influenza vaccine that could induce broad cross-influenza subtype protection would help to alleviate this burden. However, the human antibody response is intricate and often obscure, with factors like antigenic seniority or original antigenic sin "OAS", and back-boosting ensuring that each person mounts a unique immune response to infection or vaccination with any new influenza virus strain. Notably, the effects of existing antibodies on cross-protective immunity after repeated vaccinations are unclear. More research is needed to characterize the mechanisms at play, but traditional assays such as hemagglutinin inhibition (HAI) and microneutralization (MN) are excessively limited in scope and too resource-intensive to effectively meet this challenge. In the past ten years, new multiple dimensional assays (MDAs) have been developed to help overcome these problems by simultaneously measuring antibodies against a large panel of influenza hemagglutinin (HA) proteins with a minimal amount of sample in a high throughput way. MDAs will likely be a powerful tool for accelerating the study of the humoral immune response to influenza vaccination and the development of a universal influenza vaccine.

The influenza virus has been the primary cause of the pandemic, posing a constant threat to human society. Due to its genetic evolution and continuous outbreak, antiviral research currently focuses on exploring a novel lead agent. A comprehensive antiviral screening discovered a marine bacterium whose extract exerted excellent efficacy against influenza viruses. Parerythrobacter sp. M20A3S10, a novel strain under the family Erythrobacteraceae, could produce carotenoids exhibiting antiviral and anticancer activity by enhancing the cellular immune system. Post-treatment of M20A3S10 extract showed outstanding therapeutic indexes: against influenza virus A/PR8 (H1N1) [selectivity index (SI) = 24.0], A/Wisconsin/15/2009 (H3N2) (SI = 30.1) and B/Florida/78/2015 (SI = 38.2). Comparably, the effectiveness was demonstrated against Zika virus (ZIKV) and dengue virus type 2 (DENV2) with an SI of 22.5 and 24.1, respectively, namely broad-spectrum activity. Of note, the antiviral responses resulted from the common replication mechanism between IAV, ZIKV, and DENV2. The stimulation of apoptosis-mediated cellular immunity prevented the viral release and protected the host, suggesting that switching from necroptosis to apoptosis is a novel antiviral target. Although the specific compound affecting the antiviral activity was not identified, its promising efficacy with broad activity will contribute to developing a strategy for preventing future pandemics.

Human influenza A viruses (IAVs) cause global pandemics and epidemics. These viruses evolve rapidly, making current treatment options ineffective. To identify novel modulators of IAV-host interactions, we re-analyzed our recent transcriptomics, metabolomics, proteomics, phosphoproteomics, and genomics/virtual ligand screening data. We identified 713 potential modulators targeting 200 cellular and two viral proteins. Anti-influenza activity for 48 of them has been reported previously, whereas the antiviral efficacy of the remaining 665 is unknown. Studying anti-influenza efficacy, immuno-modulating properties and potential resistance of these compounds or their combinations may lead to the discovery of novel modulators of IAV-host interactions, which might be more effective than the currently available anti-influenza therapeutics.

The 2021/2022 influenza season was not characterised by a well-defined incidence peak. A high value of incidence was recorded in week 13, but it was still lower than in other influenza seasons. This abnormal circulation was probably due to relaxation of the COVID-19 pandemic restriction measures, which greatly reduced the circulation of respiratory-transmitted viruses, including human respiratory syncytial virus (HRSV). The symptoms of SARS-CoV-2 and influenza are quite similar, sharing the human-to-human transmission route via respiratory droplets. The aim of this study was to estimate the rate of coinfection with influenza viruses and/or HRSV in SARS-CoV-2-positive subjects (N=940) in a population of central Italy during the 2021/2022 season. A total of 54 cases of coinfection were detected during the study period, 51 cases (5.4%) of SARS-CoV-2 and influenza virus and three cases (0.3%) of SARS-CoV-2 and HRSV coinfection. These results highlight the importance of continuous monitoring of the circulation of influenza virus and other respiratory viruses in the context of the COVID-19 pandemic.

المستخلص تصنيع لقاح مكون من الحمض النووي الريبوزي الرسول الخاص بالبروتينات المسئولة عن انتاج البروتينات نيورامنيديز والهيم اجليوتونين لفيروسي الانفلونزا الخنازير والطيورمحاط بجزيئات دهنية بحجم النانوميتر عدوى انفلونزا الخنازير وانفلونزا الطيور مشكلة خطيرة تؤرق العالم كله هذه الايام خصوصا انها مميتة لكثير من اطفال العالم . بعد فترة التعافي من الاصابة تتكون المناعة المكتسبة ضدها لمدة عام تقريبا. هذه الانفلونزا تسبب تسمم فيروسي في الدم بالاضافة للالتهاب الرئوي وهذامن بين اكبرالاسباب للوفاة بين الاطفال قبل سن عامين عالميا بشكل مباشر. الهدف من الدراسة هو انتاج لقاح الحمض النووي الريبوزي الرسول من نوع الام بالنانوتكنولوجي لبروتينات الهيم اجليوتونين والنيورامنيديز الموجودة على سطح هذه الفيروسات التي تساعدتها في الاتصاق بالعائل الذي ستتكاثر داخل خلاياه بالجهاز التنفسي. هذه الدراسة دراسة استكشافية ومن خلالها استطاعنا تصميم هذا اللقاح باستعمال نظام توصيل للقاح بالنانوتكنولوجي حجم جزيئاته 70نانوميمتر. اللقاح الجديد اظهر فاعلية بنسبة 60% واظهر فاعلية حيوية مقاربة واثار جانبية اقل بالمقارنة باللقاحات المتوفرة حاليا بالسوق الدوائي ضد هذا النوع من الفيروسات الوبائية. ABSTRACT Background: Worldwide, Swine and Avian influenza, or the H1N1 and H5N1 serotypes of the Influenza A virus, is a highly contagious illness. In recent years, the global incidence of mortality rate has surpassed 284,000 fatalities. Aim of the study: The production of mRNA vaccine lipid nanoparticles (LNP) to combat the deadly strains of Avian and Swine influenza (H1N1 and H5N1 of the influenza A serotype). Methodology: Polymerase chain reaction (PCR) was used to clone genes of interest encoding Haemagglutinin (HA) and Neuraminidase (NA) of Influenza A virus strains (H5N1 and H1N1) known as Avian flu and Swine flu, respectively. The genes were then inserted using the EcoR1, BAM Hind II restriction endonuclease type II, and Ligase enzyme into the pET-21(+) transcription vector plasmid. On the other hand, the hybrid transcription vectors were mixed with T7 RNA polymerase and ribonucleotides within a test tube after being linearized using EcoR II. Following their purification via reversed-phase high-performance liquid chromatography (RP-HPLC), the mRNAs of the HA and NA were encased in 70 nm LNPs and subjected to reverse-phase high-performance liquid chromatography (RP-HPLC). Lastly, immunogenicity studies were performed in stages 1/2 of randomized human and preclinical clinical trials. Results: The bivalent vaccination had around 63% efficacy in preclinical studies and approximately 60% efficacy in randomized human clinical trials. As shown by the ELISA test, strong neutralizing antibodies against HA were prevalent. Conclusion: The current study is a promising effort because of the development of the novel LNP-mRNA vaccine, which could lower the incidence of Avian and Swine flu infectious disorders.

That birds are maniraptoran theropod dinosaurs is now considered an evolutionary consensus. An “open” (i.e., completely, or substantially perforate) acetabulum is considered an important synapomorphy verifying the bird-dinosaur nexus. Here I present anatomical evidence from morphological aspects of the acetabulum and its important appurtenances, the supracetabular crest and the antitrochanter, that the hip anatomy differs substantially between dinosaurs and birds and for the current hypothesis of origins to be correct unlikely anatomical reversals would have been required. Given the thin bone of the acetabular walls and the varied tissue, both hard and soft, in the acetabular region and especially the lower part of the basin, it is apparent that many avian skeletons exhibit some anatomical loss of soft tissue and thin bone, some perhaps related to changes in gait, but also in part related to the dramatic trend in bone reduction associated with flight, especially in more advanced crown taxa. Many basal birds and early diverging neornithines tend to have a nearly closed or various levels of partially closed acetabula, thus rendering the current terms “open” or “closed” acetabula inaccurate; they should be modified or replaced.

Influenza viruses cause acute respiratory infections responsible for significant mortality and morbidity around the world. Various factors, such as antigenic drift, allow influenza strains to avoid being fully suppressed by seasonal vaccines. This has led to the increased scrutiny of antivirals as treatment and prophylaxis options for seasonal outbreaks and potential pandemics. Unfortunately, many influenza antivirals suffer from a lack of adequate clinical trials, as well as a lack of toxicity data. This is especially true of umifenovir (arbidol), a drug popularly used for the prevention and treatment of influenza strains in China and Russia. Neuraminidase inhibitors, though widely prescribed, display a potential for future resistance. Adamantanes, while proven to be effective in treating influenza A, are already encountering rapid and widespread cross-resistance and are effectively obsolete. Baloxavir marboxil, a newer antiviral, shows promise in treating acute uncomplicated influenza and may avoid the development of resistance when co-administered with other antiviral drugs. Indeed, the low genetic barrier to resistance associated with influenza antivirals could potentially be overcome by co-administration with other antivirals. This review explores the most widely prescribed antivirals for influenza treatment, their mechanisms of action, and the data currently available about their susceptibility to resistance and efficacy.

Immune responses to influenza (flu) antigens reflect memory to prior infections or vaccinations, which might influence immunity to new flu antigens. Memory of past antigens has been termed “original antigenic sin” or more recently “immune imprinting” and “seniority”. We have researched a comparison between the immune response to live flu infections and inactivated flu vaccina-tions. A brief history of antibody generation theories is presented culminating in new findings about the immune-network theory suggesting that a network of clones exists between an-ti-idiotypic antibodies and T cell receptors. Findings regarding the 2009 pandemic flu strain and immune responses to it are presented, including memory B cells and conserved regions within the hemagglutinin protein. The importance of CD4+ memory T cells and cytotoxic CD8+ T cells responding to both infections and vaccinations are discussed and compared. Innate immune cells like natural killer (NK) cells and macrophages are discussed regarding their roles in adaptive immune responses. Antigen presentation via macroautophagy processes are described. New vaccines in development are mentioned along with the results of some clinical trials. The manu-script concludes with how repeated vaccinations are impacting the immune system and a sketch of what might be behind the imprinting phenomenon, including future research directions.

Neuraminidase (NA)-based immunity could reduce the harmful impact of novel antigenic variants of influenza viruses. Detection of neuraminidase-inhibiting (NI) antibodies in parallel with anti-hemagglutinin (HA) antibodies may enhance research of immunogenicity and duration of antibody response to influenza vaccines. To assess anti-NA antibodies after vaccination with seasonal inactivated influenza vaccines, we used the enzyme-linked lectin assay, and anti-HA antibodies were detected in hemagglutination inhibition assay. The dynamics of anti-NA antibody response differed depending on the virus subtype: antibodies to A/H3N2 virus neuraminidase increased later than antibodies to A/H1N1pdm09 subtype neuraminidase, and persisted longer. In contrast to HA antibodies, the fold increase in antibody titers to NA after vaccination poorly depended on the preexisting level. At the same time, NA antibody level after vaccination directly correlated with titers before vaccination. Difference was found in response to NA antigen between split and subunit adjuvanted vaccines and in NA functional activity in the vaccine formulations.

Influenza A (IAV) is a major human respiratory pathogen, causing illness, hospitalizations, and mortality annually worldwide. IAV is also a zoonotic pathogen with a multitude of hosts, allowing for interspecies transmission, reassortment events, and the emergence of novel pandemics, as was seen in 2009 with the emergence of a swine origin H1N1 (pdmH1N1) virus into humans, causing the first influenza pandemic of the 21st century. While the 2009 pandemic was considered to have high morbidity and low mortality, studies have linked the pdmH1N1 virus and its gene segments to increased disease in humans and animal models. Genetic components of the pdmH1N1 virus currently circulate in the swine population, reassorting with endemic swine viruses that co-circulate and occasionally spillover into humans. This is evidenced by the regular detection of variant swine IAVs in humans associated with state fairs and other intersections of humans and swine. Defining genetic changes that support species adaptation, virulence, and cross-species transmission, as well as mutations that enhance or attenuate these features will improve our understanding of influenza biology, aid in surveillance and virus risk assessment, and guide the establishment of counter measures for emerging viruses. Here, we review current understanding of determinants of specific IAV phenotypes, focusing on the fitness, transmission, and virulence determinants that have been identified in swine IAVs and/or in relation to the 2009 pdmH1N1 virus.

Influenza is a disease that poses a significant health burden worldwide. Vaccination is the best way to prevent influenza virus infections. However, conventional vaccines are only effective for a short period of time due to the propensity of influenza viruses to undergo antigenic drift and antigenic shift. The efficacy of these vaccines is uncertain from year-to-year due to potential mismatching between the circulating viruses and vaccine strains, mutations arising due to egg adaptation, and potential contamination of the vaccine virus stock. Subsequently, the inability to store these vaccines long-term and vaccine shortages are challenges that need to be overcome. Conventional vaccines are also less effective for certain populations, including the young, old, and immunocompromised. This warrants for diverse efficacious vaccine developmental approaches, involving both active and passive immunization. As opposed to active immunization platforms (requiring the use of whole or portions of pathogens as vaccines), the rapidly developing passive immunization involves administration of either pathogen-specific or broadly acting antibodies against a kind or class of pathogens as a prophylactic treatment to corresponding acute infection. Several antibodies with broadly acting capacities have been discovered that may serve as means to suppress influenza viral infection and allow the process of natural immunity to engage opsonized pathogens whilst boosting immune system by antibody-dependent mechanisms that bridge the innate and adaptive arms. By that, passive immunotherapeutics approach assumes a robust tool that could aid control of influenza viruses. In this review, we comment on some improvements in influenza management and promising vaccine development platforms, with emphasis on the capacity of passive immunotherapeutics especially when coupled with the use of antivirals in the management of influenza infection.

Haemosporidians are a group of vector-borne parasites belonging to the order Haemosporida. They infect avian hosts and require blood-sucking insects (Diptera) for their transmission. The occurrence and diversity of haemosporidian parasites are shaped primarily by the specificity of the parasite and the susceptibility of the host/vector. In this study, the presence and distribution of haemosporidians in blood samples from birds in urbanized and natural habitats were estimated using microscopic and molecular approaches. Birds in urbanized habitats were infected with four different species of Plasmodium: Plasmodium relictum, P. vaughani, P. matutinum, P. circumflexum, two different species of Haemoproteus: Haemoproteus majoris, H. parabelopolskyi, and Leucocytozoon sp. The species, H. attenuatus, H. concavocentralis, H. minutus, H. pallidus, H. noctue and H. tartakovskyi were additionally identified in birds in natural habitats. Typically, juvenile birds are essential markers of parasite species transmitted in the study area. The juveniles in the urbanized habitats carried the P. relictum, P. vaughani, P. circumflexum, H. parabelopolskyi, H. majoris, and Leucocytozoon species. The most abundant parasite was H. parabelopolskyi, which was found in both types of habitats. The prevalence of the Haemoproteus/Plasmodium species by nested PCR in birds in natural habitats (in totally 43.80%; 53/121) was significantly higher than that in birds in urbanized habitats (in totally 21.94%; 43/196) (p < 0.05), even in spring. There was no statistically significant difference between habitat types in overall infection rate of Leucocytozoon sp. (p > 0.05; 10/121 vs. 19/196), neither overall nor in the spring.

Abstract: More than 40 hypotheses predict associations between features of nest architecture and at least one measure of reproductive success. However, quantitative studies of reproductive consequences of nest characteristics remain scarce. In addition, most studies were conducted on model species of which nests can be easily monitored with artificial nest-boxes. Here we review the replicability of research protocols and findings in model species with many repeat studies focusing mainly on nest-size components, animal-derived nest material, or fresh greenery in blue tits (Cyanistes caeruleus), great tits (Parus major), tree swallows (Tachycineta bicolor), and starlings (Sturnus spp.). The studies looked for correlations between nest traits and aspects of breeding performance that can be easily quantified in the field, such clutch size, brood size at hatching or fledging, the % of eggs that hatch or fledge, or nestling characteristics assumed to reflect qualities associated with survival probabilities (e.g., morphometry, body condition, blood profiles). We discuss the consequences of poor replicability of research methodologies and provide explanations for why many of these studies reported poor associations between nest design and breeding success at different spatiotemporal scales. We also make suggestions for future research. Keywords: Nest design, Breeding success, Nest-box, Cavity-nesting birds, Replicability

Human influenza A viruses (IAVs) cause global pandemics and epidemics, which remain serious threats to public health because of the shortage of effective means of control. To combat the surge of viral outbreaks, new treatments are urgently needed. Developing new virus control modalities requires better understanding of virus-host interactions. Here we describe how IAV infection triggers cellular apoptosis, and how this process can be exploited towards development of new therapeutics, which might be more effective than the currently available anti-influenza drugs.

Emerging RNA virus infections are a growing concern among domestic bird and poultry industries due to the severe impact it can have on the flock health and economic livelihoods. Avian paramyxoviruses (APMV) are pathogenic, negative sense RNA viruses that cause serious infections in the respiratory and central nervous system. APMV was detected in multiple avian species during the 2017 migration season in Ukraine, and studied using PCR, virus isolation, and sequencing. Of the 4090 wild bird samples, eleven swabs were isolated in chicken embryos and identified for APMV serotype by hemagglutinin inhibition test: APMV-1, APMV-4, APMV-6, APMV-7. At a variety of sites in Ukraine we characterized the virulence of the virus and further analyzed and predicted the potential risks of spillover to immunologically naïve populations. RNA was extracted and amplified using a multiplex-tiling primer approach to encompass full cDNA genomes. Full-length APMV-1 (n=5) and APMV-6 (n=2) genomes were sequenced on an Oxford Nanopore MinION device in Ukraine. All APMV-1 and APMV-6 fusion (F) proteins possessed a monobasic cleavage site, suggesting these APMV were likely low virulence, annually circulating strains. Utilization of this low-cost method will identify gaps in viral evolution and circulation in this understudied but important critical region for Eurasia.

The world is in the grips of the COVID-19 pandemic. Public health measures that can reduce the risk of infection and death in addition to quarantines are desperately needed. This article reviews the roles of vitamin D in reducing risk of respiratory tract infections, knowledge about the epidemiology of influenza and COVID-19, and how vitamin D supplementation might be a useful measure to reduce risk. Through several mechanisms, vitamin D can reduce risk of infections. Those mechanisms include inducing cathelicidins and defensins that can lower viral replication rates and reducing concentrations of pro-inflammatory cytokines that produce the inflammation that injures the lining of the lungs, leading to pneumonia, as well as increase concentrations of anti-inflammatory cytokines. Several observational studies and clinical trials reported that vitamin D supplementation reduced risk of influenza, whereas others did not. Evidence supporting the role of vitamin D in reducing risk of COVID-19 includes that the outbreak occurred in winter, a time when 25-hydroxyvitamin D [25(OH)D] concentrations are lowest; that the number of cases in the Southern Hemisphere near the end of summer are low; that vitamin D deficiency has been found to contribute to acute respiratory distress syndrome, and that case-fatality rates increase with age and with chronic disease comorbidity, both of which are associated with lower 25(OH)D concentration. To reduce risk of infection, it is recommended that people at risk of influenza and/or COVID-19 consider taking 10,000 IU/d of vitamin D₃ for a few weeks to rapidly raise 25(OH)D concentrations, followed by 5000 IU/d. The goal should be to raise 25(OH)D concentrations above 40–60 ng/ml (100–150 nmol/l). For treatment of people who become infected with COVID-19, higher vitamin D₃ doses might be useful. Randomized controlled trials and large population studies should be conducted to evaluate these recommendations.

Background: Night-migratory birds sense the Earth´s magnetic field by an unknown molecular mechanism. Theoretical and experimental evidence support the hypothesis that light-induced formation of a radical-pair in European robin cryptochrome 4a, ErCry4a, is the primary signalling step in the retina of the bird. In the present work, we investigated a possible route of cryptochrome signalling involving the α-subunit of the cone specific heterotrimeric G protein from European robin. Methods: Protein-protein interaction studies include surface plasmon resonance, pulldown affinity binding and Förster resonance energy transfer. Results: Surface plasmon resonance studies showed direct interaction revealing high to moderate affinity for binding of non-myristoylated and myristoylated G protein to ErCry4a, respectively. Pulldown affinity experiments confirmed this complex formation in solution. We validated these in vitro data by monitoring the interaction between ErCry4a and G protein in a transiently transfected neuroretinal cell line using Förster resonance energy transfer. Conclusions: Our results suggest that ErCry4a and the G protein also interact in vivo and might constitute the first biochemical signalling step in radical-pair-based magnetoreception.

United States is the largest producer and the second largest exporter of broiler meat in the world. In the U.S, broiler production is largely converting to antibiotic-free programs which has caused an increase in morbidity and mortality within broiler farms. Escherichia coli and Clostridium perfringens are two important pathogenic bacteria readily found in the broiler environment and result in annual billion-dollar losses from colibacillosis, gangrenous dermatitis, and necrotic enteritis. Broiler industry is in search of non-antibiotic alternatives including novel vaccines, prebiotics, probiotics, and housing management strategies to mitigate production losses due to these diseases. This review provides an overview of the broiler industry and antibiotic free production, current challenges, and emerging research on antibiotic alternatives to reduce pathogenic microbial presence and improve bird health.

Avipoxvirus (APV), a linear dsDNA virus belonging to the subfamily Chordopoxvirinae of the family Poxviridae, infects more than 278 species of domestic and wild birds. It is responsible for causing the avian pox disease, which is characterized by its cutaneous and diphtheric forms. With a high transmission capacity, it can cause high economic losses and damage to the ecosys-tem. Several diagnostic methods are available and vaccination of birds can be an effective pre-ventive measure. To update the molecular characterization and phylogenetic analysis of viruses isolated in Portugal between 2017 and 2023, ten APV-positive samples were analyzed. A P4b gene fragment was amplified by PCR and the nucleotide sequence of the amplicons was deter-mined by Sanger sequencing. The sequences obtained were aligned using ClustalW, and a max-imum likelihood phylogenetic tree was constructed. With this study, it was possible to verify that the analyzed sequences are distributed in subclades A1, A2, B1, and B3. Since some of them are quite similar to others from different countries and obtained in different years, it is possible to conclude that there have been several viral introductions in Portugal. Finally, it was possible to successfully update the data on avipoxviruses in Portugal.

COVID-19 infection, caused by SARS-CoV-2, is inequitably distributed and more lethal among populations with lower socioeconomic status. Direct contact with contaminated surfaces has been one of the virus sources, as it remains infective up to days. Several disinfectants have been shown to inactivate SARS-CoV-2 but they rapidly evaporate, are flammable or toxic and may be scarce or inexistent for the vulnerable populations. Therefore, we are proposing a simple, easy to prepare, low-cost and efficient antiviral films, made with wide available dishwasher detergent, which can be spread in hands and inanimate surfaces and maintains virucidal activity for longer periods than the current sanitizers. Avian coronavirus (ACoV) was used as model of challenge to test the antivirus efficacy of proposed films. Polystyrene microplates were covered with a thin layer of detergent formula. After drying, the films were exposed to different virus doses for 10 minutes and virus infectivity were determined using embryonated chicken eggs and RNA virus quantification in allantoic fluids by RT-qPCR. The films showed to inactive the ACoV (ranging from 103.66 to 106.66 EID50), which is chemically and morphologically similar to SARSCoV-2 and may constitute an excellent alternative to minimize the spread of Covid-19.

Influenza A viruses (IAVs) evolve via point mutations and reassortment of viral gene segments. The patterns of reassortment in different host species differ considerably. We investigated the genetic diversity of IAVs in wild ducks and compared it with the viral diversity in gulls. The complete genomes of 38 IAVs of H1N1, H1N2, H3N1, H3N2, H3N6, H3N8, H4N6, H5N3, H6N2, H11N6 and H11N9 subtypes isolated from wild mallard duck and gull habitants of a pond in Moscow city, Russia were sequenced. The sequences were closely related to those of avian IAVs isolated in Sweden and the Netherlands. The analysis of phylogenetic trees showed that stable viral genotypes do not persist from year to year in ducks owing to frequent gene reassortment. For comparison, similar analyses were carried out using sequences of IAVs isolated in the same period from ducks and gulls in the Netherlands. Our results revealed a significant difference in diversity and rates of reassorment of IAVs in ducks and gulls.

The COVID-19 pandemic remains a serious public health problem globally. During winter flu seasons, more aggressive SARS-CoV-2 infections with fatalities have been documented, indicating that influenza co-infections may significantly impact the disease outcome of COVID-19. Both influenza and SARS-CoV-2 viruses share many similarities in their transmission and cellular tropism for their replication in the human respiratory tract. However, it is still unclear how the two pathogens interplay to ensure their survival in the same lung microenvironment. In addition, clinical studies on influenza co-infections in COVID-19 patients do not provide conclusive evidence on how influenza co-infection mechanistically modifies the disease outcome in COVID-19. This mini-review discusses various viral as well as host factors that potentially influence the survival or synergism of these two respiratory pathogens in the infected lung microenvironment.

Background: On late December 2019, a viral pneumonia known as coronavirus disease 2019 (COVID-19), was originated from China and spread very rapidly in the world. Therefore, COVID-19 became a global concern and health problem. Methods: We presented four patients in this study. They were selected from patients who presented with pneumonia symptoms and were suspicious for COVID-19 and referred to the intended centers for COVID-19 diagnosis and management of Shiraz University of Medical Sciences in the south of Iran. Two nasopharyngeal and oropharyngeal throat swab samples were collected from each patient and tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detection by real-time reverse-transcriptase–polymerase-chain-reaction (RT-PCR), and also samples were sent for influenza viruses and all the respiratory panel. Results: In the present report, four patients were diagnosed in the starting days of COVID-19 disease in our center in south of Iran with co-infection of SARS-CoV-2 and influenza virus. Conclusions: This co-infection of COVID-19 and influenza highlights the importance of considering SARS-CoV-2 PCR assay regardless of other positive findings for other pathogens in the primary test during the epidemic.

This paper presents a study of human blood sera samples, collected in various regions of the Russian Federation, with regard to both vaccine and pandemic avian influenza viral strains. Just before the 2022-2023 epidemic season, herd immunity to seasonal influenza A viruses was reportedly lower than before the COVID-19 pandemic. Since no stable circulation of A/H5Nx and A/H9N2 influenza in the human population was observed during this period, we believe 100% vaccination against seasonal influenza is necessary for employees of poultry farms and other organizations, closely connected to the breeding and processing of poultry. In addition to protection against seasonal influenza, vaccination can hamper the emergence of new viral variants, driven by genome reassortment, during simultaneous infection of humans with seasonal human and animal influenza viruses.

Cellular oxidation is responsive to external and internal stimulation and is generated via signal molecules in defense mechanisms through networks of cell proliferation, differentiation, intracellular detoxification, bacterial infection, and immune reactions. Oxidative stress is not necessarily harmful per se; it depends on the balance between oxidation and antioxidation cascades, which are induced according to stimuli and can maintain oxygen homeostasis. The reactive oxygen species (ROS) that are generated during influenza virus (IV) infection have critical effects on both the virus and host cells. In this review, we outline the link between viral infection and ROS production, using IV as an example. We introduce the current state of knowledge on the molecular relationship between cellular oxidation mediated by ROS production and various effects of IV infection. We also summarize the potential anti-IV agents that act by targeting oxidative stress.

Vaccination attitudes among healthcare workers (HCWs) is a vital factor for measuring their level of vaccination uptake and intention to recommend vaccinations to their patients. To our knowledge, no study has been conducted in South Africa to assess hesitancy to influenza vaccines among HCWs. We used questionnaire adapted from Betsch and colleagues to conduct an online and face-to-face cross-sectional study among HCWs at the start of COVID-19 vaccine roll-out prior to the flu season. Main outcome was influenza vaccine hesitancy. We used multivariate logistic regression to assess predictors of influenza vaccine hesitancy. Of 401 participants, 64.5% were women, 49.2% nurses, and 12.5% physicians. A total of 54.9% were willing to accept vaccination, 20.4% were undecided, and 24.7% intended to refuse. Older participants above 17-25 years and physicians were likely to receive the vaccine. Key predictors of vaccine acceptance were confidence in the effectiveness, consideration of benefits and risks, and willingness to be vaccinated to protect others. Influenza vaccine hesitancy was highest in those who did not trust that influenza vaccines are safe. For future flu seasons, tailored education programs targeting younger HCWs and more information about the composition of flu vaccines would be vital to improve vaccine uptake.

The evolution of some epidemics, as influenza, shows common patterns both in different regions and from year to year. On the contrary, epidemics like the novel COVID-19 show quite heterogeneous dynamics and are extremely susceptible to the measures taken to mitigate their spread. In this paper we propose empirical dynamic modeling to predict the evolution of influenza in Spain’s regions. It is a non-parametric method that looks into the past for coincidences with the present to make the forecasts. Here we extend the method to predict the evolution of other epidemics at any other starting territory and we test also this procedure with Spanish COVID-19 data. We finally build influenza and COVID-19 networks to check possible coincidences in the geographical distribution of both diseases. With this, we grasp the uniqueness of the geographical dynamics of COVID-19.

The chicken embryo is a widely used experimental animal-model in many studies such as developmental biology and to study the physiological responses and adaptation to altered environments as well as for cancer and neurobiology research. Embryonic heart rate is an important physiological variable useful as an index reflecting the embryo's natural activity and is considered one of the most difficult parameters to measure. An acceptable measurement technique of embryonic heart rate should provide a reliable cardiac signal quality while maintaining adequate gas exchange through the eggshell along the incubation and embryonic developmental period. In this paper, we presented a detailed design and methodology for a non-invasive PPG-based prototype (Egg-PPG) for real-time and continuous monitoring of embryonic heart rate during incubation. An automatic embryonic cardiac wave detection algorithm, based on normalised spectral entropy, is described. The developed algorithm successfully estimated the embryonic heart rate with 98.7% accuracy. We believe that the developed overall system presented in this paper is showing a promising solution for non-invasion, real-time monitoring of embryonic cardiac signal, which can be used in both experimental studies (e.g., developmental embryology and cardiovascular research) and in industrial incubation applications.

Avian mutations in vaccine strains obtained from embryonated eggs could impair vaccine effec-tiveness. We performed a systematic review and meta-analysis of the adjusted relative vaccine effectiveness (arVE) of seed cell-cultured influenza vaccines (ccIV) compared to egg-based influ-enza vaccines (eIV) in preventing laboratory-confirmed influenza related outcomes (IRO) or IRO by clinical codes, in subjects 18 and over. We completed the literature search in January 2021; ap-plied exclusion criteria, evaluated risk of bias of the evidence, and performed heterogeneity, pub-lication bias, qualitative, quantitative and sensitivity analyses. All estimates were computed us-ing a random approach. International Prospective Register of Systematic Reviews, CRD42021228290. We identified 12 publications that reported 26 adjusted arVE results. Five publications reported 13 laboratory confirmed arVE and seven reported 13 code-ascertained arVE. Nine publications with 22 results were at low risk of bias. Heterogeneity was explained by season and risk of bias. We found a significant 11% (8 to 14%) adjusted arVE favoring ccIV in preventing any IRO in the 2017-2018 influenza season. The arVE was 3% (-01 to 7%) in the 2018-2019 influenza season. We found moderate evidence of a significant advantage of the ccIV in preventing IRO, compared to eIV, in a well-matched A(H3N2) predominant season.

There are scarce data regarding flu vaccination among people with HIV infection (PWHIV). The goal of this explorative study is to assess hesitancy toward influenza vaccination in a group of PWHIV during the pandemic. A questionnaire was administered to 219 patients vaccinated at our clinic during the 2020-2021 campaign. It evaluated subjects’ adherence over the last 3 seasonal vaccination campaigns, vaccine confidence, complacency and convenience, and the effect of the pandemic on the choice to vaccinate. The population was divided into two groups: fully adherent (all 3 campaigns, 117 patients) and non-fully adherent (1 or 2 campaigns, 102 patients). Adherence increased in non-fully adherent group in 2020-2021, but the pandemic did not affect the choice. Misbelieves emerged: influenza vaccine was considered protective SARS-CoV-2 (22.8% of total population); almost half of all patients thought influenza vaccine could improve their CD4+ cell level (57.3% in fully adherent, 40.2% in non-fully adherent, p<0.05). A quarter of the non-fully adherent group would not have vaccinated in a location other than our clinic (24.5% vs 11.9% in fully adherent group, p<0.05). Conclusively, offering a secure and private space for vaccination seems to encourage vaccination; healthcare professionals should improve counselling to increase adherence and correct misbeliefs.

Over the years influenza B virus (IBV) contribute annual disease and can lead to serious respiratory disease among humans. More attention should be paid to the mammalian adaptive processes of B viruses and development of vaccines against current influenza. Because of preclinical trials of anti-influenza drugs are conducted mainly on mice, we developed adequate animal model using antigenically-relevant IBV strain for testing anti-influenza drugs and protective efficacy of flu vaccines. We serially passaged Victoria lineage (clade 1A) IBV 17 times in BALB/c mice. The adaptive amino acid substitutions were found in HA (T214I) and NA (D432N). By the electron microscopic examination, we showed spherical and elliptical shapes of IBV. Light microscopy showed that mouse-adapted B virus caused influenza pneumonia on day 6 post inoculation. We evaluated the illness pathogenicity, viral load and histopathological features of mouse-adapted IBV and estimated anti-influenza drugs and vaccine efficiency in vitro and in vivo. Assessment of investigational anti-influenza drug oseltamivir ethoxisuccinate and flu vaccine Ultrix® revealed effectivity against our mouse-adapted influenza B virus.

Nanoparticle-assisted polymerase chain reaction (nanoPCR) is a novel method for rapid detection of pathogens. A sensitive and specific multiple nanoPCR assay was developed for simultaneous detection of three subgroups avian leucosis virus (ALV). In this study, three pairs of primers that were designed based on gp85 gene sequences of subgroup A, B and J, optimizations were carried out for better performance of the nanoPCR assay and remarkably improved the detection limit of the assay. The detection limit of the assay was 101copies/μl, which was 100-fold more sensitive than conventional PCR assays. The nanoPCR assay amplified the specific 336 bp, 625 bp and 167 bp fragments of ALV-A, -B and –J respectively and no cross-reactivity were found with the genomic DNA or cDNA of Newcastle disease virus, avian infectious laryngotracheitis virus, Marek's disease virus, infectious bronchitis vaccine, infectious bursal disease virus and avian encephalomyelitis Virus. To evaluate the detection ability of the assay, 186 clinical samples were detected by nanoPCR and the detection results were further confirmed by sequencing. The sequencing results were 100% in coincidence with the nanoPCR detection results, suggesting the possibility of clinical application of the newly developed nanoPCR assay. Taking all the results together, a highly specific and sensitive nanoPCR was successfully developed, which could be useful for rapid diagnosis of ALV in poultry farming.

The enteric nervous system (ENS) is principally derived from vagal neural crest cells that migrate caudally along the entire length of the gastrointestinal tract, giving rise to neurons and glial cells in two ganglionated plexuses. Incomplete migration of enteric neural crest-derived cells (ENCDC) leads to Hirschsprung disease, a congenital disorder characterized by the absence of enteric ganglia along variable lengths of the colorectum. Our recent data [1] support an essential role for the avian ceca, present at the junction of midgut and hindgut, in hindgut ENS development, since ablation of the cecal buds leads to incomplete ENCDC colonization of the hindgut. In situ hybridization shows bone morphogenetic protein-4 (BMP4) highly expressed in the cecal mesenchyme, leading us to hypothesize that cecal BMP4 is required for hindgut ENS development. To test this, we modulated BMP4 activity using embryonic intestinal organ culture techniques and retroviral infection in ovo. We show that overexpression or inhibition of BMP4 in the ceca disrupts hindgut ENS development, with GDNF playing an important regulatory role. Our results suggest that these two important signaling pathways are required for normal ENCDC migration and enteric ganglion formation in the developing hindgut ENS.

Seasonal influenza is a common cause of hospital admission, especially in older people and those with comorbidities. The objective of this study was to determine influenza vaccine effectiveness (VE) in preventing intensive care admissions and shortening the length of stay (LOS) in hospitalized laboratory-confirmed influenza cases (HLCI) in Catalonia (Spain).A retrospective cohort study was carried out during the 2017-2018 season in HLCI aged ≥ 18 years from 14 public hospitals. Differences in means and proportions were assessed using a t-test or a chi-square test as necessary and the differences were quantified using standardized effect measures; Cohen’s d for quantitative and Cohen’s w for categorical variables. Adjusted influenza vaccine effectiveness in preventing severity was estimated by multivariate logistic regression where the adjusted VE = (1-adjusted odds ratio) ·100%; adjustment was also made using the propensity score.We analyzed 1414 HLCI aged ≥ 18 years; 465 (33%) were vaccinated, of whom 437 (94%) were aged ≥ 60 years, 269 (57.8%) were male and 295 (63.4%) were positive for influenza type B. ICU admission was required in 214 (15.1%) cases. There were 141/1118 (12.6%) ICU admissions in patients aged ≥ 60 years and 73/296 (24.7%) in those aged < 60 years (p<0.001). The mean LOS and ICU LOS did not differ significantly between vaccinated and unvaccinated patients. There were 52/465 (11.2%) in vaccinated cases) ICU admissions in vaccinated cases vs. 162/949 (17.1%) in unvaccinated cases. Patients admitted to the ICU had a longer hospital LOS (mean: 22.4 [SD 20.3] days) than those who were not (mean: 11.1 [SD14.4] days); p<0.001. Overall, vaccination was associated with a lower risk of ICU admission. Taking virus types A and B together, the estimated adjusted VE in preventing ICU admission was 31% (95% CI 1-52; p=0.04). When stratified by viral type, the aVE was 40% for type A (95% CI -11-68; p = 0.09) and 25% for type B (95% CI -18-52; p = 0.21). Annual influenza vaccination may prevent ICU admission in cases of HLCI. A non-significantly shorter mean hospital stay was observed in vaccinated cases. Our results support the need to increase vaccination uptake and public perception of the benefits of influenza vaccination in groups at a higher risk of hospitalization and severe outcomes.

Background: Influenza vaccine is a tool for preventing infection and reducing exacerbations in patients with asthma and chronic obstructive pulmonary disease (COPD). Purpose of this study is to investigate dynamics of CRP and serum cytokines (IL-2, IL-6, IL-10, IL-17) in patients with asthma and COPD, as well as to perform a correlation analysis with the clinical parameters of the disease manifestation. Methods: The study included 34 patients with asthma, 20 patients with COPD vaccinated against influenza during a period of remission from 2 to 4 weeks, both groups being under a basic maintenance therapy, and 26 healthy individuals vaccinated with the trivalent polymer-subunit vaccine Grippol® Plus, containing 5 µg of influenza virus strains and 500 µg of azoximer bromide. Results: Observing patients with asthma and COPD, during a year after the vaccination, has revealed a significant reduction in exacerbations frequency (p < 0.05) and duration (p < 0.05) of the bronchial obstructive syndrome (BF). Before the vaccination the IL-6 level in patients with asthma had a direct moderate correlation with duration of exacerbations of the underlying disease (p < 0.05), along with the number of systemic corticosteroids courses during exacerbations (p < 0.05). In 12 months after the vaccination, while assessing cytokine profile of all study groups, a significant reduction in the level of IL-6 was observed, compared to the baseline values (p< 0.05). Conclusion: Conducted analysis of immunological, clinical, and functional parameters of patients with asthma and COPD has proven for influenza vaccine to be effective in BF patients.

Aim: Streptococcus pneumoniae and influenza H1N1 virus are common organisms associated with human infections. These infections could play a significant role in immune regulation. The study was performed to analyse the genome sequences of these organisms with human genome and study its functional significance. Methods: The study was performed to analyse the overlapping of genome sequences in Streptococcus pneumoniae and Influenza (H1N1) virus against human genome sequences by BLASTn sequence analysis. The alignments are studied against the corresponding genes for their functional significance with DAVID and NDEx software.Results: Several hits or overlapping nucleotide segments were identified. Between streptococcus and homo sapiens 287 overlaps were identified, and among influenza and homo sapiens 124 hits were identified. A wide range of functional significance of these genes were identified, and the results are presented in this study. The results show insights into functional pathways and biological activities associated with the respective vaccinations or infections by these microorganisms. Conclusion: The common organisms like Streptococcus pneumoniae and Influenza H1N1 virus actively interact with the immune system and result in a wide range of immune regulations.

T cell function is determined by transcriptional networks that are regulated by epigenetic programming via posttranslational modifications (PTMs) of histone proteins and DNA. Bottom-up mass spectrometry (MS) can identify histone PTMs, whereas intact protein analysis with high-field Fourier transform ion cyclotron resonance MS (FTICR-MS) can detect species missed by bottom-up approaches. We used high-resolution reversed-phase liquid chromatography (RPLC) FTICR-MS, alternating electron transfer dissociation (ETD) and collision-induced dissociation (CID) on precursor ions to maximize fragmentation of uniquely modified species. First online RPLC separation sorted histone families then weak cation exchange hydrophilic interaction liquid chromatography (WCX-HILIC) separated species heavily clad in PTMs. Tentative PTM identifications were assigned by matching peptide masses to predicted theoretical masses that were verified with tandem MS. We used this innovative approach for Histone-intact protein PTM mapping (HiPTMap) and to quantify PTMs on core histones purified from CD8+ T cells directly isolated ex vivo post-influenza infection. Activation significantly reduced PTMs in vivo following influenza infection, histone maps changed as T cells migrated to infections, and T cells responding to secondary heterologous infections had significantly more PTMs enhancing transcriptional activation. Thus, HiPTMap identifies and quantifies PTMs on CD8+ T cell histones and determines their combinations in T cell states.

Chronic obstructive pulmonary disease (COPD) patients are particularly susceptible to respiratory infections like influenza, which exacerbate symptoms and increase healthcare utilization. While smoking cessation and influenza vaccination are recommended preventive measures, their combined impact on healthcare resource utilization is underexplored. The Charlson Comorbidity Index (CCI) assesses comorbidity burden in COPD patients and may influence healthcare outcomes. We conducted a retrospective analysis of 357 COPD patients, evaluating smoking cessation success over one year and influenza vaccination receipt, stratifying patients by CCI scores. Healthcare utilization outcomes included emergency room visits, hospitalizations, and medical expenses. Results showed that 51.82% of patients quit smoking and 59.66% received influenza vaccination, with higher comorbidity prevalence in advanced COPD stages (p=0.002). Both smoking cessation and influenza vaccination independently correlated with decreased emergency room visits, hospital admissions, days, and costs. Patients who both quit smoking and received influenza vaccination exhibited the lowest healthcare utilization rates. In conclusion, smoking cessation and influenza vaccination significantly reduce healthcare resource utilization in COPD patients, with the combination yielding synergistic benefits, particularly in those with lower CCI scores. Integrating these interventions and comorbidity management in COPD strategies is essential for optimizing patient outcomes and healthcare efficiency.

Immune surveillance by natural killer (NK) cells and their recruitment to sites of inflammation renders them susceptible to viral infection, potentially modulating their effector function. Here, we analyzed innate RNA receptor signaling in NK cells downstream of direct Influenza A virus (IAV) infection and its impact on NK cell effector function. Infection of NK cells with IAV resulted in the activation of TBK1, NF-κB and subsequent type-I IFN secretion. CRISPR- generated knockouts in primary human NK cells revealed that this effect depended on the antiviral cytosolic RNA receptor RIG-I. Transfection of NK cells with synthetic 3p-dsRNA, a strong RIG-I agonist that mimics viral RNA, resulted in a similar phenotype and rendered NK cells resistant to subsequent IAV infection. Strikingly, both IAV infection and 3p-dsRNA transfection enhanced degranulation and cytokine production by NK cells when exposed to target cells. Thus, RIG-I activation in NK cells both supports their cell intrinsic viral defense and enhances their cytotoxic effector function against target cells.

Respiratory tract infections (RTIs) are one of the main causes of hospitalization and mortality causing substantial economic burden to healthcare systems globally. As opposed to the previous belief that respiratory infections are caused by a single pathogen, studies have shown that most RTIs are a result of a combination of bacterial and/or viral pathogens infecting the host. The clinical manifestation of RTIs is very similar (i.e., syndrome), often showing Influenza-like illness (ILI) symptoms. While COVID-19 has dominated ILI over the past few years, there are many other pathogens that are responsible for ILI. In addition, it is not uncommon to have coinfections with multiple pathogens in patients presenting with ILI and that such coinfections can even exacerbate the disease severity of RTIs. Therefore, an insight into coinfections can help with accurate disease prognosis, patient care management and outcomes. The goal of this study was to identify the different organisms in symptomatic patients presenting with ILI.

Airborne transmission of seasonal and pandemic influenza viruses is responsible for their epidemiological success and public health burden in humans. Efficient airborne transmission of H1N1 influenza virus relies on receptor specificity and pH of fusion of the surface glycoprotein hemagglutinin (HA). In this study, we examine the role of HA pH of fusion on transmissibility of a cell culture-adapted H3N2 virus. Mutations in the HA head at positions 78 and 212 of A/Perth/16/2009 (H3N2), which were selected after cell culture adaptation, decrease the acid stability of the virus from a pH of 5.5 (WT) to 5.8 (mutant). In addition, we observed that this mutant H3N2 virus replicated to higher titers in cell culture but had reduced airborne transmission in the ferret model. These data demonstrate that, like H1N1 HA, the pH of fusion for H3N2 HA is a determinant of efficient airborne transmission. Surprisingly, we demonstrate that the NA segment noncoding regions can impact the pH of fusion of reassortant viruses. Taken together, our data confirm that HA acid stability is an important characteristic of epidemiologically successful human influenza viruses and is influenced by HA/NA balance.

Mice are not natural hosts for influenza A viruses (IAVs), but they are useful models for studying antiviral immune responses and pathogenesis. Serial passage of IAV in mice invariably causes the emergence of adaptive mutations and increased virulence. Typically, mouse-adaptation studies are conducted in inbred laboratory strains BALB/c and C57BL/6, which have defects in the antiviral Mx1 gene that results in increased susceptibility to infection and disease severity. Here, we report the adaptation of IAV reference strain A/California/07/2009(H1N1) (a.k.a. CA/07) in outbred Swiss Webster mice. Serial passage led to increased virulence and lung titers, and dissemination of the virus to brains. We adapted a deep-sequencing protocol to identify and enumerate adaptive mutations across all genome segments. Among mutations that emerged during mouse-adaptation, we focused on amino acid substitutions in polymerase subunits: polymerase basic-1 (PB1) T156A and F740L, and polymerase acidic (PA) E349G. These mutations were evaluated singly and in combination in minigenome replicon assays, which revealed that PA E349G increased polymerase activity. By selectively engineering these three adaptive PB1 and PA mutations into the parental CA/07 strain, we demonstrated that adaptive mutations in polymerase subunits decreased the production of defective viral genome segments with internal deletions, and dramatically increased the release of infectious virions from mouse cells. Together, these findings increase our understanding of the contribution of polymerase subunits to successful host adaptation.

After the discovery of Corynebacterium glutamicum from the avian feces contaminated soil, its enigmatic L-glutamate secretion by corynebacterial MscCG-type mechanosensitive channels has been utilized for the industrial monosodium glutamate production. Bacterial mechanosensitive channels are activated directly by increased membrane tension upon hypoosmotic downshock, thus the physiological significance of the corynebacterial L-glutamate secretion has been considered as adjusting turgor pressure by releasing cytoplasmic solutes. In this review, we present information that corynebacterial mechanosensitive channels have been evolutionally specialized as carriers to secrete L-glutamate into the surrounding environment in their habitats rather than osmotic safety valves. The lipid modulation activation of MscCG channels in L-glutamate production can be explained by the “Force-From-Lipids” and “Force-From-Tethers” mechanosensing paradigms and differs significantly from the mechanical activation upon hypoosmotic shock. The review also provides information on the search for possibilities that Corynebacterium glutamicum was originally a gut bacterium in the avian host in the aim of understanding physiological roles of corynebacterial mechanosensing. Corynebacterium glutamicum is able to secrete L-glutamate by mechanosensitive channels in the gut microbiota and help the host brain function via the microbiota-gut-brain axis.

Influenza is well-known to have a considerable influence on healthcare system, therefore, vaccination plays a significant role in dealing with severe consequences. Close attention is paid to the development of tetravalent adjuvanted vaccines, containing antigens of two influenza A subtypes (H1N1, H3N2) and two influenza B subtypes (Victoria, Yamagata) to increase the effectiveness of influenza prevention. In this work we present the results of pre-clinical study of innovative subunit tetravalent candidate influenza vaccine, with addition of betulin as adjuvant, TetraFluBet. The study was conducted using female BALB/c mice, male and female mongrel rats and guinea pigs. TetraFluBet and commercially available vaccines were injected intraperitoneally twice in a 14-day interval after intranasal infection with 5LD50 and 10LD50. Chronic toxicity was assessed by immunohistochemistry of extracted organs and by hematological and biochemical blood parameters. Protectivity and immunogenicity were evaluated using hemagglutination inhibition and microneutralization with MDCK assays. Chronic toxicity study did not reveal any side effects of candidate TetraFluBet vaccine on both rats and guinea pigs. One vaccination dose of TetraFluBet provided 100% protectivity against all 4 influenza subtypes and significantly increased neutralizing antibody activity in response to immunization of influenza subtypes. Pre-clinical candidate vaccine TetraFluBet confirmed its safety along with specific activity, showed high immunogenicity and can be recommended for further clinical studies.

Influenza epidemics in temperate regions display dynamics that are characterized by pronounced seasonal peaks during the winter. The general lack of influenza cases during the off-season may result from the virus physically disappearing at the end of the season, in which case it must be imported annually. Alternatively, it may result from persistent asymptomatic carriers or unnoticed local transmission chains that develop into local epidemics as conditions become conducive. Here I attempt to understand these differing explanations by analyzing the global distribution of the four major subtypes that comprise influenza over a period of 18 years based on FluNet data, the surveillance network and database compiled by the WHO, and the NCBI influenza data resource, a repository of relevant genetic information. Examining the annual proportion of each subtype, I find considerable variations in subtype annual proportions between the regions. Moreover, I find that seasonal influenza subtypes can remain confined to specific temperate regions, without showing measurable global presence. These results indicate that although largely undetected during the off-season, influenza is likely to persist locally, and imply a ‘local-global’ model where annual influenza epidemics are a mixture of local strains undergoing reactivation together with an influx of global variants.

Herein, we developed a highly sensitive and specific bimolecular fluorescence complementation (BiFC)-based influenza A virus (IAV) sensing system created by combining a galactose/glucose-binding protein (GGBP) with an N-terminal large domain (YN1-172) and a C-terminal small domain (YC173-239) of enhanced yellow fluorescence protein (eYFP). The GGBP-based BiFC reporter exhibits the fluorescence reconstitution as a result of conformational changes in GGBP when lactose, derived from 6’-silalyllactose used as a substrate for neuraminidase (NA), binds to GGBP in the presence of IAV. The system showed a linear dynamic range from 1 x 100 TCID50/mL to 1 x 107 TCID50/mL, with a detection limit of 4 x 101 TCID50/mL for IAV (H1N1), demonstrating ultra-high sensitivity. Our system exhibited fluorescence intensity enhancements in the presence of IAV, while displaying weak fluorescence signals when exposed to NA-deficient viruses such as RSV A, RSV B, adenovirus and rhinovirus, thereby indicating selective responses for IAV detection. Taken together, our system provides a simple, highly sensitive and specific IAV detection platform based on BiFC capable of detecting the ligand-induced protein conformational changes, obviating the need for virus culture or RNA extraction processes.

The purpose of this work was to longitudinally investigate the dynamic evolution of vaccine hesitancy towards both COVID-19 and influenza. We followed a cohort of 479 adult patients at Udine Hospital (Italy) having in common a medical history of SARS-CoV-2 infection in 2020, during the first and most impactful pandemic wave. Vaccine attitude was assessed through standardized telephone interviews performed at 12 and 18 months after the acute illness. The background of the survey was represented by COVID-19 vaccination campaign, started with the approval of the first vaccine in December 2020 and bolstered by the introduction of Green Pass in July 2021, in a context where anti-vaccination beliefs and mistrust in healthcare system were rising. The first interview reported the success of the 2020/21 seasonal influenza immunization with 46.8% (224/479) of the participants showing a positive attitude, especially the elderly and people with comorbidities (p&lt; 0.001). The investigation conducted at 18 months showed a drastic drop in flu shot acceptance (30/166, 18.1%), the reluctance being justified by the feeling of protection regardless of prevention (55.8%) and by concerns regarding vaccines safety and efficacy (23.3%). In parallel, a great increase in vaccinations against SARS-CoV2 occurred after the introduction of Green Pass (72.9% vs 26.7%), although only a minority of the participants identified in the restrictions induced by the certification the leading incentive to get immunized (22.3%). Vaccine hesitancy remains a dynamic and complex phenomenon, which is difficult to overcome with incentive or obligatory strategies alone. The purpose of achieving vaccine compliance should always take into account the social and political context, as well as the role of personal opinions and emotions.

The pathogenesis of porcine circovirus type 2b (PCV2b) and swine influenza A virus (SwIV) during co-infection in swine respiratory cells is poorly understood. To elucidate the impact of PCV2b/SwIV co-infection, newborn porcine tracheal epithelial cells (NPTr) and immortalized porcine alveolar macrophages (iPAM 3D4/21) were co-infected with PCV2b and SwIV (H1N1 or H3N2 genotype). Viral replication, cell viability and cytokine mRNA expression were determined and compared between single-infected and co-infected cells. Finally, 3’mRNA sequencing was performed to identify the modulation of gene expression and cellular pathways in co-infected cells. It was found that PCV2b significantly decreased and improved SwIV replication, in co-infected NPTr and iPAM 3D4/21 cells respectively, compared to single infected cells. Interestingly, PCV2b/SwIV co-infection synergistically up-regulated IFN expression in NPTr cells whereas in iPAM 3D4/21 cells, PCV2b impaired the SwIV IFN induced response, both correlating with SwIV replication modulation. RNA-sequencing analyses revealed that the modulation of gene expression and enriched cellular pathways during PCV2b/SwIV H1N1 co-infection is regulated in a cell type-dependent-manner. This study revealed different outcomes of PCV2b/SwIV co-infection in porcine epithelial cells and macrophages and provides new insights on porcine viral co-infections pathogenesis.

The first exposure to influenza is thought to impact subsequent immune responses later in life. The consequences of this can be seen during influenza epidemics and pandemics with differences in morbidity and mortality for different birth cohorts. There is a need for better understanding of how vaccine responses are affected by early exposures to influenza viruses. In this analysis of hemagglutination inhibition (HI) antibody responses in two cohorts of military personnel we noticed differences related to age, sex, prior vaccination, deployment and birth year. These data suggest that HI antibody production, in response to influenza vaccination, is affected by these factors. The magnitude of this antibody response is associated with, among other factors, the influenza strain that circulated following birth.

Influenza B virus (IBV) is considered a major respiratory pathogen responsible for seasonal respiratory disease in humans, particularly severe in children and the elderly. Seasonal influenza vaccination is considered the most efficient strategy to prevent and control IBV infections. Live attenuated influenza virus vaccines (LAIVs) are thought to induce both humoral and cellular immune responses by mimicking a natural infection, but their effectiveness have recently come into question. Thus, the opportunity exists to find alternative approaches to improve overall influenza vaccine effectiveness. Two alternative IBV backbones were developed with re-arranged genomes, re-arranged M (FluB-RAM) and a re-arranged NS (FluB-RANS). Both re-arranged viruses showed temperature sensitivity in vitro compared to the WT type B/Bris strain, were genetically stable over multiple passages in embryonated chicken eggs and were attenuated in vivo in mice. In a prime-boost regime in naïve mice, both re-arranged viruses induced antibodies against HA with hemagglutination inhibition titers considered of protective value. In addition, antibodies against NA and NP were readily detected with potential protective value. Upon lethal IBV challenge, mice previously vaccinated with either FluB-RAM or FluB-RANS were completely protected against clinical disease and mortality. In conclusion, genome re-arrangement renders efficacious LAIV candidates to protect mice against IBV.

We evaluated the change in water dispersibility of lactic acid bacteria (LAB, Enterococcus faecalis KH2) upon powderization and its influence on their efficacy. When cultured LAB are washed, heat-killed, and powdered, adhesion between LAB occurs and they form aggregation (non-treated LAB, n-LAB). However, a dispersed LAB (d-LAB) powder with less aggregates can be prepared by treating them with a high-pressure homogenizer and adding an excipient during powdering. n-LAB or d-LAB was administered to mice and the Peyer's patches in the small intestine were observed. n-LAB administration showed a high amount of aggregated LAB drifting in the intestinal mucosa, whereas d-LAB reached the Peyer's patches and was taken up into the Peyer's patches. Evaluation in a mouse influenza virus infection model showed that d-LAB was more effective than n-LAB in influenza yield of bronchoalveolar lavage fluids (BALFs) on day 3 post-infection, neutralizing antibody titers of sera and influenza virus-specific IgA in the feces on day 14 post-infection. Thus, the physical properties of LAB affect their efficacy; controlling their water dispersibility can improve their effectiveness.

Influenza virus infection causes severe respiratory illness in people worldwide, disproportionately affecting infants. The immature respiratory tract coupled with the developing immune system is thought to synergistically play a role in the increased disease severity in younger age groups. Although vaccines remain the best solution for protecting this vulnerable population, no vaccines are available for those under 6 months, and for infants aged 6 months to 2 years, the vaccine elicits a dampened immune response. Dampened immune responses may be due to unique features of the infant immune system and a lack of pre-existing immunity. Unlike older children and adults, the infant immune system is Th2 skewed and has less antigen presenting cells and soluble immune factors. Paradoxically, we know that a person’s first infection with the influenza virus during infancy or childhood leads to the establishment of life-long immunity toward that particular virus strain. This is called influenza imprinting. To provide better protection against influenza virus infection and disease in infants, more research must be conducted to understand the imprinting event. We contend that by understanding influenza imprinting in the context of the infant immune system and the infant’s immature respiratory tract, we will be able to design more effective influenza vaccines for both infants and adults. Working through the lens of imprinting, using infant influenza animal models such as mice and ferrets, which have proven useful for infant immunity studies, we will gain a better understanding of imprinting and its implications regarding vaccine design. This review examines literature regarding infant immune development, current vaccine strategies, respiratory development, and the importance of researching the imprinting event in infant animal models to develop more effective and protective vaccines for young children.

Avian metapneumovirus subgroup C (aMPV/C) causes respiratory diseases and egg dropping in chickens and turkeys, resulting in severe economic losses to the poultry industry worldwide. Integrin β1 (ITGB1), a transmembrane cell adhesion molecule, is present in various cells and mediates numerous viral infections. Herein, we demonstrate that ITGB1 is essential for aMPV/C infection in cultured DF-1 cells, as evidenced by the inhibition of viral binding by EDTA blockade, Arg-Ser-Asp (RSD) peptide, monoclonal antibody against ITGB1, and ITGB1 short interfering (si) RNA knockdown in cultured DF-1 cells. Simulation of the binding process between the aMPV/C fusion (F) protein and avian-derived ITGB1 using molecular dynamics showed that ITGB1 may be a host-factor for benefiting aMPV/C attachment or internalization. Transient expression of avian ITGB1 rendered porcine and feline non-permissive cells (DQ cells and CRFK cells, respectively) susceptible to aMPV/C infection. Replication kinetic of aMPV/C in siRNA-knockdown cells revealed that ITGB1 plays an important role in aMPV/C infection at the early stage (attachment and internalization). aMPV/C was also able to infect efficiently human non-small cell lung cancer (A549) cells. This may be due to a consequence of the similar structures of both metapneumovirus F protein-specific motifs (RSD for aMPV/C and RGD for human metapneumovirus) recognized by ITGB1. Overexpression of avian-derived ITGB1 and human-derived ITGB1 in A549 cells enhanced aMPV/C infectivity. Taken together, this study demonstrated that ITGB1 acts as an essential receptor for aMPV/C attachment and internalization into host cells in which facilitates aMPV/C infection.

Influenza is a highly contagious, acute respiratory illness, which represents one of the main health issues worldwide. Even though some antivirals are available, the alarming increase of virus strains resistant to them highlights the need to find new drugs. Previously, Superti et al. have deeper investigated the mechanism of the anti-Influenza virus effect of bovine Lactoferrin (bLf) and the role of its tryptic fragments (the N and C-lobes) in the antiviral activity. Recently, through a truncation library, we identified the tetrapeptides, SKHS (1) and SLDC (2), derived from bLf C-lobe fragment 418-429, which were able to bind hemagglutinin (HA) and inhibit cell infection in a concentration range of femto- to picomolar. Starting from these results, in this work, we initiated a systematic SAR study on the peptides mentioned above, through an Alanine scanning approach. We carried out binding affinity measurements by microscale thermophoresis (MST) and Surface Plasmon Resonance (SPR), and hemagglutination inhibition (HI) and virus neutralization (NT) assays on synthesized peptides. Computational studies were performed to identify possible lig-and-HA interactions. Results obtained led to the identification of an interesting peptide endowed with broad anti-Influenza activity and able to inhibit viral infection to a greater extent of reference peptide.

The role of T cell immunity has been acknowledged in recent vaccine development and evaluation. We tested the humoral and cellular immune responses to Flucelvax®, a quadrivalent inactivated seasonal influenza vaccine containing two influenza A (H1N1 Singapore/GP1908/2015 IVR-180 and H3N2 North Carolina/04/2016) and two influenza B (Iowa/06/2017 and Singapore/INFTT-16-0610/2016) virus strains, using peripheral blood mononuclear cells stimulated by pools of peptides overlapping all the individual influenza viral protein components. Baseline reactivity was detected against all four strains both at the level of CD4 and CD8 responses and targeting different proteins. CD4 T cell reactivity was mostly directed to HA/NA proteins in influenza B strains, and NP/M1/M2/NS1/NEP proteins in the case of the Influenza A strains. CD8 responses to both influenza A and B viruses preferentially targeted the more conserved core viral proteins. Following vaccination, both CD4 and CD8 responses against the various influenza antigens were increased in day 15 to day 91 post vaccination period and maintained a Th1 polarized profile. Importantly, no vaccine interference was detected, with the increased responses balanced across all 4 included viral strains for both CD4 and CD8 T cells, and targeting HA and multiple additional viral antigens.

Fabric material was coated with Viruferrin™ and tested for its inactivating properties against the pandemic severe acute respiratory syndrome 2 (SARS-CoV-2) and influenza A viruses. A statistically significant (p<0.0001) decrease in the number of infectious virus particles exposed to Viruferrin-treated fabric when compared with the cotton control for both SARS-CoV-2 and influenza A viruses was observed. For both SARS-CoV-2 and influenza A, Viruferrin-treated fabrics experienced a > 99% virus reduction without saliva after five minutes of contact when compared to the positive control at time point 0. Furthermore, the reusability of the Viruferrin treated fabric was demonstrated by stability for up to 10 washes. The level of anti-viral (SARS-CoV-2) activity remained constant from 5 to 10 washes and demonstrated a significant difference (p<0.0001) from the unwashed untreated material. Applications for this treated fabric are far-reaching, and as a biological face covering offers not only a unique 2-way protection but also is unlikely to cause onward touch transmission.

With an estimated 3 to 5 million human cases annually and the potential to infect domestic and wild animal populations, influenza viruses are one of the greatest health and economic burdens to our society [1] and pose an ongoing threat of large-scale pandemics. Despite our knowledge of many important aspects of influenza virus biology, there is still much to learn about how influenza viruses replicate in infected cells, for instance how they use entry receptors or exploit host cell trafficking pathways. These gaps in our knowledge are due, in part, to the difficulty of directly observing viruses in living cells. In recent years, advances in light microscopy, including super-resolution microscopy and single-molecule imaging, have enabled many viral replication steps to be visualised dynamically in living cells. In particular, the ability to track single virions and their components, in real time, now allows specific pathways to be interrogated providing new insights to various aspects of the virus-host cell interaction. In this review, we discuss how state-of-the-art imaging technologies, notably quantitative live-cell and super-resolution microscopy, are shedding new nanoscale and molecular insights into influenza virus replication and revealing new opportunities for developing antiviral strategies.

Influenza virus imprinting is now understood to significantly the influence immune responses and clinical outcome of influenza virus infections that occur later in life. Due to the yearly cycling of influenza viruses, humans are imprinted with the circulating virus of their birth year to subsequently build a complex influenza virus immune history but very little is known about how the imprinting strain influences vaccine responses. To investigate the imprinted host immune responses to split-virion vaccination, we imprinted ferrets with a sublethal dose of the historical seasonal H1N1 strain A/USSR/90/1977. After a +60 day recovery period was given to build immune memory, ferrets were immunized and the challenge at Day 123. Samples were collected throughout the time course and immunological assays were performed to investigate recall mechanisms. The preimmune-vaccinated ferrets did not experience significant disease during challenge while naïve-vaccinated ferrets had severe disease. Hemagglutination inhibition assays showed preimmune ferrets had a more robust antibody response post vaccination, increased virus neutralization activity. Virus specific immunoglobulins were of predominantly the IgG isotype suggesting B cell maturity and plasticity at vaccination. These results are important and should be considered for vaccine design.

Since 2007, highly pathogenic clade 2.3.2 H5N1 avian influenza A [A(H5N1)] viruses have evolved to clade 2.3.2.1a, b and c, and currently only 2.3.2.1c A(H5N1) viruses circulate in wild birds and poultry. During antigenic evolution, clade 2.3.2.1a and c A(H5N1) viruses acquired both S144N and V223I mutations around the receptor binding site of hemagglutinin (HA), with S144N generating an N-glycosylation sequon. We introduced single or combined reverse mutations, N144S and/or I223V, into the HA gene of clade 2.3.2.1c A(H5N1) virus and generated PR8-derived, 2 + 6 recombinant A(H5N1) viruses. When we compared replication efficiency in embryonated chicken eggs, mammalian cells and mice, the recombinant virus containing both N144S and I223V mutations showed increased replication efficiency in avian and mammalian hosts and pathogenicity in mice. The N144S mutation significantly decreased avian receptor affinity and egg white inhibition, but not all mutations increased mammalian receptor affinity. Interestingly, the combined reverse mutations dramatically increased the thermostability of HA. Therefore, the adaptive mutations possibly acquired to evade avian immunity may decrease viral thermostability as well as mammalian pathogenicity.

Avian necrotic enteritis is an enteric disease of broiler chickens caused by certain pathogenic strains of Clostridium perfringens in combination with predisposing factors. A vaccine offering complete protection against the disease has not yet been commercialized. In a previous study, we produced five recombinant proteins predicted to be surface-exposed and unique to necrotic enteritis-causing C. perfringens and the immunogenicity of these potential vaccine candidates was assessed in broiler chickens. In the current work, the relative contribution of the antibodies raised by these putative antigens to protect broiler chickens was evaluated using an experimental necrotic enteritis induction model. Additionally, the link between the immune response elicited and the gut microbiota profiles in immunized birds subjected to infection with virulent C. perfringens was studied. ELISA results showed that the IgY antibody titers in vaccinated birds on days 21 and 33 were significantly higher than those on days 7 and 14 and those in birds receiving the adjuvant alone, while the relative contribution of the specific immunity attributed to these antibodies could not be precisely determined using this experimental NE induction model. Besides, 16S rRNA gene amplicon sequencing showed that immunization of birds with recombinant proteins had a low impact on the chicken caecal microbiota.

Haemosporidian parasites, including Haemoproteus, Plasmodium, and Leucocytozoon, are intracellular parasites found in the blood and tissues of birds worldwide. The prevalence of these parasites varies depending on bird species and habitats. Humidity, influenced by water availability, is one of the factors affecting their prevalence. In this study, we collected 145 blood samples from wild songbirds in the western region of Iran from April to November 2021-2022. Blood smears were prepared using the push-slide method and stained with Giemsa. The stained smears were examined under a light microscope. Among the seven songbird families sampled, blood parasites were detected in 31 individuals from five families. Of these, 23 individuals (15.86%) were from humid areas, while 8 individuals (5.51%) were from dry areas. The highest infection rates were observed in the Paridae (9.65%) and Motacilliidae (4.82%) families, while the lowest infection rates were found in the Corvidae (1.37%) and Acrocephalidae (1.37%) families. We recorded two new hosts for Leucocytozoon spp. (Motacilla flava and Acrocephalus melanopogon) for the first time in the world and four new host records (Motacilla flava, Pica pica, Acrocephalus melanopogon, and Acrocephalus agricola) for blood parasites in the west of Iran. Our findings highlight the high prevalence of avian blood parasites in songbirds inhabiting humid areas, suggesting that these environments provide suitable conditions for the growth and reproduction of invertebrate hosts.

Synthetic antivirals and corticosteroids have been used to treat both influenza and the SARS-CoV-2 disease named COVID-19. However, these medications are not always effective, produce several adverse effects, and are associated with high costs. Medicinal plants and their constituents act in several different targets and signaling pathways involved in the pathophysiology of Influenza and COVID-19. This study aimed to perform a review to evaluate the effects of medicinal plants on Influenza and COVID-19 and to investigate the potential delivery systems for new antiviral therapies. EMBASE, PubMed, GOOGLE SCHOLAR, and COCHRANE databases were searched. The studies included in this review showed that medicinal plants, in different formulations, can help decrease viral spread and time of full recovery. Plants reduced the incidence of acute respiratory syndromes and the symptom scores of the illnesses. Moreover, plants are related to few adverse effects and have low costs. In addition to their significance as natural antiviral agents, medicinal plants and their bioactive compounds may exhibit low bioavailability. This highlights the need for alternative delivery systems, such as metal nanoparticles, that can effectively transport these compounds to infected tissues.

Influenza viruses pose a continuing public health challenge due to their high mutation rate and the need for annual vaccine updates. A recent advancement in nanoparticle-based vaccine technology for developing a universal influenza vaccine. We focused on four key studies investigating the use of lipid nanoparticles (LNPs), nanoparticle immunogens, and multivalent epitope-based nanoparticles. The studies demonstrated promising results. The single-dose mRNA -LNP vaccine targeting five influenza B virus antigens effectively protected mice from a broad range of strain. Additionally, nanoparticle immunogens designed to display multiple influenza virus strains induced broad protective immunity in mice. Furthermore, LNPs enhanced the efficacy of mRNA and protein subunit vaccines by stimulating robust T follicular helper cell and humoral responses. Finally, an intranasal multivalent epitope-based nanoparticle vaccine offered broad protection against diverse influenza viruses. These findings highlight the potential of nanoparticle-based approaches for developing a universal influenza vaccine that offers long-lasting and broad-spectrum protection. Further research is needed to evaluate the safety and efficacy of these novel vaccines in humans.

Three autonomous communities have been the ones that, in the 2022-2023 season, anticipated the document approved by the Public Health Commission, recommending influenza vaccination for all children aged 6 to 59 months. The main objective of this work is to evaluate the attitude of healthcare professionals towards the first universal vaccination campaign in our region, as well as the acceptability of the vaccines used and the attitude towards the piloting of school vaccination. Cross-sectional, survey-based, descriptive study. All healthcare professionals involved in the campaign were invited to participate. The 91.9% of surveyed professionals thought that flu vaccination from 6 to 59 months was important or very important. 89.8% had previous experience regarding the intramuscular vaccine. The professionals valued the intranasal vaccine significantly more positively; however, there were no differences when asking for each of the vaccines without comparison. The inhaled vaccine was preferred by 97.5% for the following campaign. Piloted school vaccination showed 75% acceptance. The inhaled vaccine was preferred by most professionals and the piloted school vaccination was highly accepted, and independently associated to the importance of vaccination as considered by physicians, being a medical doctor, and participation in the pilot program.