H5 Influenza Research Articles

Deep mutational scanning of H5 hemagglutinin to inform influenza virus surveillance

H5 influenza is considered a potential pandemic threat. Recently, H5 viruses belonging to clade 2.3.4.4b have caused large outbreaks in avian and multiple nonhuman mammalian species. Previous studies have identified molecular phenotypes of the viral hemagglutinin (HA) protein that contribute to pandemic potential in humans, including cell entry, receptor preference, HA stability, and reduced neutralization by polyclonal sera. However, prior experimental work has only measured how these phenotypes are affected by a handful of the >10,000 different possible amino-acid mutations to HA. Here, we use pseudovirus deep mutational scanning to measure how all mutations to a 2.3.4.4b H5 HA affect each phenotype. We identify mutations that allow HA to better bind α2-6-linked sialic acids and show that some viruses already carry mutations that stabilize HA. We also measure how all HA mutations affect neutralization by sera from mice and ferrets vaccinated against or infected with 2.3.4.4b H5 viruses. These antigenic maps enable rapid assessment of when new viral strains have acquired mutations that may create mismatches with candidate vaccine virus, and we show that a mutation present in some recent H5 HAs causes a large antigenic change. Overall, the systematic nature of deep mutational scanning combined with the safety of pseudoviruses enables comprehensive measurements of the phenotypic effects of mutations that can inform real-time interpretation of viral variation observed during surveillance of H5 influenza.

From emergence to endemicity of highly pathogenic H5 avian influenza viruses in Taiwan

A/goose/Guangdong/1/96-like (GsGd) highly pathogenic avian influenza (HPAI) H5 viruses cause severe outbreaks in poultry when introduced. Since emergence in 1996, control measures in most countries have suppressed local GsGd transmission following introductions, making persistent transmission in domestic birds rare. However, geographical expansion of clade 2.3.4.4 sublineages has raised concern about establishment of endemic circulation, while mechanistic drivers leading to endemicity remain unknown. We reconstructed the evolutionary history of GsGd sublineage, clade 2.3.4.4c, in Taiwan using a time-heterogeneous rate phylogeographic model. During Taiwan’s initial epidemic wave (January 2015 - August 2016), we inferred that localised outbreaks had multiple origins from rapid spread between counties/cities nationwide. Subsequently, outbreaks predominantly originated from a single county, Yunlin, where persistent transmission harbours the trunk viruses of the sublineage. Endemic hotspots determined by phylogeographic reconstruction largely predicted the locations of re-emerging outbreaks in Yunlin. The transition to endemicity involved a shift to chicken-dominant circulation, following the initial bidirectional spread between chicken and domestic waterfowl. Our results suggest that following their emergence in Taiwan, source-sink dynamics from a single county have maintained GsGd endemicity up until 2023, pointing to where control efforts should be targeted to eliminate the disease.

Vaccine Quality Challenges in Secretly Traded H5 and H9 Avian Influenza Vaccines in Nigeria

Avian Influenza Virus (AIV) especially the highly pathogenic subtype H5Nx causes Avian Influenza (AI) disease and it is a major threat to the poultry industry and public health worldwide. Vaccination is one of the control measures in many countries, though restricted in Nigeria. As such, some poultry farmers secretly employ imported H5 and H9 AI vaccines to vaccinate their chickens. This study investigated the antigenic quality of these imported vaccines. Four imported vaccine brands were tested using Hemagglutination (HA) test and Reverse Transcriptase Polymerase Chain Reaction (RTPCR). All four vaccine samples tested negative in the HA test, indicating a lack of detectable HA antigen titer. Similarly, RT-PCR failed to amplify the targeted region of the viral matrix gene in any of the vaccine samples against reference control. These negative results are of great concern and suggest that the imported H5 and H9 vaccines lack essential antigens that could stimulate antibodies. Thus, potentially rendering them ineffective against circulating AI subtypes. The failure in antigenic quality could be due to myriads of factors including improper storage, transport (often due to illegal import), or limitations in the original vaccine production process. Regardless of the specific cause, these findings highlight the potential risks associated with the use of unregulated vaccines. Poultry farmers who use these imported vaccines may be incurring unnecessary costs while receiving a false sense of security for their flocks. In conclusion, due to the apparent lack of efficacious antigens, we suggest a quality monitoring of imported H5 and H9 vaccines in Nigeria for compliance with local regulations on vaccine use, biosecurity measures and investigation into the root causes of the vaccine failure observed in this study.

Conserved sites on the influenza H1 and H3 hemagglutinin recognized by human antibodies.

Monoclonal antibodies (mAbs) targeting the influenza hemagglutinin (HA) have the potential to be used as prophylactics or templates for next-generation vaccines that provide broad protection. Here, we isolated broad, subtype-neutralizing mAbs from human B cells targeting the H1 or H3 HA head as well as a unique mAb targeting the stem. The H1 mAbs target the previously defined lateral patch epitope on H1 HAs and recognize HAs from 1933 to 2021 in addition to a swine H1N1 virus with pandemic potential. Using directed evolution, we improved the neutralization potency of these H1 mAbs towards a contemporary H1 strain. Using deep mutational scanning of four antigenically distinct H1N1 viruses, we identified potential viral escape pathways. For the H3 mAbs we used cryo-EM to define the targeted epitopes: one mAb recognizes the side of the H3 head, accommodating the N133 glycan and a pocket underneath the receptor binding site. The other H3 mAb recognizes an epitope in the HA stem that overlaps with previously characterized mAbs, but with distinct antibody variable genes and mode of recognition. Collectively, these mAbs identify common sites recognized by broad, subtype-specific mAbs that may be elicited by next-generation vaccines.

Immune History Modifies Disease Severity to HPAI H5N1 Clade 2.3.4.4b Viral Challenge.

The most recent outbreak of highly pathogenic avian H5 influenza (HPAI) virus in cattle is now widespread across the U.S. with spillover events happening to other mammals, including humans. Several human cases have been reported with clinical signs ranging from conjunctivitis to respiratory illness. However, most of those infected report mild to moderate symptoms, while previously reported HPAI H5Nx infections in humans have had mortality rates upwards of 50%. We recently reported that mice with pre-existing immunity to A/Puerto Rico/08/1934 H1N1 virus were protected from lethal challenge from highly pathogenic clade 2.3.4.4b H5N1 influenza virus. Here, we demonstrate that mice infected with the 2009 pandemic H1N1 virus strain A/California/04/2009 (Cal09) or vaccinated with a live-attenuated influenza vaccine (LAIV) were moderately-to-highly protected against a lethal A/bovine/Ohio/B24OSU-439/2024 H5N1 virus challenge. We also observed that ferrets with mixed pre-existing immunity-either from LAIV vaccination and/or from Cal09 infection-showed protection against a HPAI H5N1 clade 2.3.4.4b virus isolated from a cat. Notably, this protection occurred independently of any detectable hemagglutination inhibition titers (HAIs) against the H5N1 virus. To explore factors that may contribute to protection, we conducted detailed T cell epitope mapping using previously published sequences from H1N1 strains. This analysis revealed a high conservation of amino acid sequences within the internal proteins of our bovine HPAI H5N1 virus strain. These data highlight the necessity to explore additional factors that contribute to protection against HPAI H5N1 viruses, such as memory T cell responses, in addition to HA-inhibition or neutralizing antibodies.

Human pathogen nucleic acids in wastewater solids from 191 wastewater treatment plants in the United States

We measured concentrations of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants, influenza A and B viruses, respiratory syncytial virus, human metapneumovirus, enterovirus D68, human parainfluenza types 1, 2, 3, 4a, and 4b in aggregate, norovirus genotype II, rotavirus, Candida auris, hepatitis A virus, human adenovirus, mpox virus, H5 influenza A virus, and pepper mild mottle virus nucleic acids in wastewater solids prospectively at 191 wastewater treatment plants in 40 states across the United States plus Washington DC. Measurements were made two to seven times per week from 1 January 2022 to 30 June 2024, depending on wastewater treatment plant staff availability. Measurements were made using droplet digital (reverse-transcription–) polymerase chain reaction (ddRT-PCR) following best practices for making environmental molecular biology measurements. These data can be used to better understand disease occurrence in communities contributing to the wastewater.

An mRNA vaccine candidate encoding H5HA clade 2.3.4.4b protects mice from clade 2.3.2.1a virus infection

Highly pathogenic avian influenza (HPAI) H5 viruses from different clades have been circulating globally, threatening wild/domestic birds and mammals. Given frequent spillovers and high mortality among mammals, coupled with our inability to predict which clade of H5 virus has pandemic potential, cross-clade protective HPAI H5 vaccines are urgently needed. Here, we demonstrate the applicability of a lipid nanoparticle-based mRNA vaccine modality to induce cross-protective immunity against lethal HPAI virus infection.

Spatial patterns of influenza A virus spread across compartments in commercial swine farms in the United States.

Multiple genetic variants of H1 and H3 influenza A viruses (IAVs) circulate concurrently in US swine farms. Understanding the spatial transmission patterns of IAVs among these farms is crucial for developing effective control strategies and mitigating the emergence of novel IAVs. In this study, we analysed 1909 IAV genomic sequences from 785 US swine farms, representing 33 farming systems across 12 states, primarily in the Midwest from 2004 to 2023. Bayesian phylogeographic analyses were performed to identify the dispersal patterns of both H1 and H3 virus genetic lineages and to elucidate their spatial migration patterns within and between different systems. Our results showed that both intra-system and inter-system migrations occurred between the swine farms, with intra-system migrations being more frequent. However, migration rates for H1 and H3 IAVs were similar between intra-system and inter-system migration events. Spatial migration patterns aligned with expected pig movement across different compartments of swine farming systems. Sow-Farms were identified as key sources of viruses, with bi-directional migration observed between these farms and other parts of the system, including Wean-to-Finish and Gilt-Development-Units. High intra-system migration was detected across farms in the same region, while spread to geographically distant intra- and inter-system farms was less frequent. These findings suggest that prioritizing resources towards systems frequently confronting influenza problems and targeting pivotal source farms, such as sow farms, could be an effective strategy for controlling influenza in US commercial swine operations.

Pichia pastoris an Ideal Host for the Production of Recombinant Influenza Vaccines

Pichia pastoris is a methylotrophic yeast with remarkable characteristics such as lacking endotoxin, producing high amounts of recombinant protein, performing post-translational modifications, and so on. Influenza A virus, a member of the Orthomyxoviridae family, is the cause of avian influenza. Three avian influenza virus subtypes, H5, H7 and H9, are commercially and physiologically significant in the poultry industry. Some researchers considered influenza to be the next pandemic disease. Nowadays, researchers have paid attention to producing novel and effective recombinant vaccines, especially in the poultry industry. Due to the advantages of P. pastoris yeast, it can be used as an ideal expression system for producing subunit vaccines. Although several studies have been conducted in this field, there is no comprehensive review of using P. pastoris to produce recombinant influenza vaccines. This review explains the different strains, phenotypes, and advantages of this yeast and then the production of recombinant influenza vaccines using this expression system is discussed in detail.

Highly pathogenic avian influenza (HPAI) H5 virus exposure in domestic cats and rural stray cats, the Netherlands, October 2020 to June 2023.

BackgroundHighly pathogenic avian influenza (HPAI) H5Nx and human H1N1pdm2009 influenza viruses can infect cats. Infections in cats may result in viral adaptations or recombinant viruses, which may facilitate zoonotic transfer.AimWe aimed to investigate the presence of HPAI H5 clade 2.3.4.4 and H1 influenza viruses and antibodies to these viruses in domestic and rural stray cats in the Netherlands and factors associated with exposure.MethodsSera from stray and domestic cats, sampled 2020-2023, were analysed by ELISA and confirmed by hemagglutination inhibition assay (HAI) and pharyngeal swabs and lung tissue for influenza A virus by RT-qPCR.ResultsIn 701 stray cats, 83 (11.8%; 95% confidence interval (CI): 9.5-14.5) sera were positive for HPAI H5 and 65 findings were confirmed. In HAI, two sera were positive for both HPAI H5 and H1. In 871 domestic cats, four (0.46%; 95% CI: 0.13-1.2) sera were HPAI H5 positive and none were confirmed but 40 (4.6%; 95% CI: 3.3-6.2) sera were seropositive for H1 and 26 were confirmed. Stray cats living in nature reserves (odds ratio (OR) = 5.4; 95% CI: 1.5-20.1) and older cats (OR = 3.8; 95% CI: 2.7-7.1) were more likely to be HPAI H5 seropositive. No influenza A virus was detected in 230 cats.ConclusionThe higher HPAI H5 seroprevalence in stray cats compared with domestic cats suggests more frequent viral exposure, most likely due to foraging on wild birds. In contrast, exposure to H1 was more common in domestic cats compared with stray cats.

Molecular Characterization of a Clade 2.3.4.4b H5N1 High Pathogenicity Avian Influenza Virus from a 2022 Outbreak in Layer Chickens in the Philippines.

H5 subtype high-pathogenicity avian influenza (HPAI) viruses continue to devastate the poultry industry and threaten food security and public health. The first outbreak of H5 HPAI in the Philippines was reported in 2017. Since then, H5 HPAI outbreaks have been reported in 2020, 2022, and 2023. Here, we report the first publicly available complete whole-genome sequence of an H5N1 high-pathogenicity avian influenza virus from a case in Central Luzon. Samples were collected from a flock of layer chickens exhibiting signs of lethargy, droopy wings, and ecchymotic hemorrhages in trachea with excessive mucus exudates. A high mortality rate of 96-100% was observed within the week. Days prior to the high mortality event, migratory birds were observed around the chicken farm. Lungs, spleen, cloacal swabs, and oropharyngeal-tracheal swabs were taken from two chickens from this flock. These samples were positive in quantitative RT-PCR assays for influenza matrix and H5 hemagglutinin (HA) genes. To further characterize the virus, the same samples were subjected to whole-virus-genome amplification and sequencing using the Oxford Nanopore method with mean coverages of 19,190 and 2984, respectively. A phylogenetic analysis of the HA genes revealed that the H5N1 HPAI virus from Central Luzon belongs to the Goose/Guangdong lineage clade 2.3.4.4b viruses. Other segments also have high sequence identity and the same genetic lineages as other clade 2.3.4.4b viruses from Asia. Collectively, these data indicate that wild migratory birds are the likely source of H5N1 viruses from the 2022 outbreaks in the Philippines. Thus, biosecurity practices and surveillance for HPAI viruses in both domestic and wild birds should be increased to prevent and mitigate HPAI outbreaks.

Immunity and Protective Efficacy of a Plant-Based Tobacco Mosaic Virus-like Nanoparticle Vaccine against Influenza a Virus in Mice.

The rapid production of influenza vaccines is crucial to meet increasing pandemic response demands. Here, we developed plant-made vaccines comprising centralized consensus influenza hemagglutinin (HA-con) proteins (H1 and H3 subtypes) conjugated to a modified plant virus, tobacco mosaic virus (TMV) nanoparticle (TMV-HA-con). We compared immune responses and protective efficacy against historical H1 or H3 influenza A virus infections among TMV-HA-con, HA-con protein combined with AddaVax™ adjuvant, and whole-inactivated virus vaccine (Fluzone®). Immunogenicity studies demonstrated robust IgG, IgM, and IgA responses in the TMV-HA-con and HA-con protein vaccinated groups, with relatively low induction of interferon (IFN)-γ+ T-cell responses across all vaccinated groups. The TMV-HA-con and HA-con protein groups displayed partial protection (100% and 80% survival) with minimal weight loss following challenge with two H1N1 strains. The HA-con protein group exhibited 80% and 100% survival against two H3 strains, whereas the TMV-HA-con groups showed reduced protection (20% survival). The Fluzone® group conferred 20-100% survival against two H1N1 strains and one H3N1 strain, but did not protect against H3N2 infection. Our findings indicate that TMV-HA and HA-con protein vaccines with adjuvant induce protective immune responses against influenza A virus infections. Furthermore, our results underscore the potential of plant-based production using TMV-like nanoparticles for developing influenza A virus candidate vaccines.

Utilizing machine learning and hemagglutinin sequences to identify likely hosts of influenza H3Nx viruses

Influenza is a disease that represents both a public health and agricultural risk with pandemic potential. Among the subtypes of influenza A virus, H3 influenza virus can infect many avian and mammalian species and is therefore a virus of interest to human and veterinary public health. The primary goal of this study was to train and validate classifiers for the identification of the most likely host species using the hemagglutinin gene segment of H3 viruses. A five-step process was implemented, which included training four machine learning classifiers, testing the classifiers on the validation dataset, and further exploration of the best-performing model on three additional datasets. The gradient boosting machine classifier showed the highest host-classification accuracy with a 98.0 % (95 % CI [97.01, 98.73]) correct classification rate on an independent validation dataset. The classifications were further analyzed using the predicted probability score which highlighted sequences of particular interest. These sequences were both correctly and incorrectly classified sequences that showed considerable predicted probability for multiple hosts. This showed the potential of using these classifiers for rapid sequence classification and highlighting sequences of interest. Additionally, the classifiers were tested on a separate swine dataset composed of H3N2 sequences from 1998 to 2003 from the United States of America, and a separate canine dataset composed of canine H3N2 sequences of avian origin. These two datasets were utilized to look at the applications of predicted probability and host convergence over time. Lastly, the classifiers were used on an independent dataset of environmental sequences to explore the host identification of environmental sequences. The results of these classifiers show the potential for machine learning to be used as a host identification technique for viruses of unknown origin on a species-specific level.

Codon optimized influenza H1 HA sequence but not CTLA-4 targeting of HA antigen to enhance the efficacy of DNA vaccines in an animal model

Infections caused by the influenza virus lead to both epidemic and pandemic outbreaks in humans and animals. Owing to their rapid production, safety, and stability, DNA vaccines represent a promising avenue for eliciting immunity and thwarting viral infections. While DNA vaccines have demonstrated substantial efficacy in murine models, their effectiveness in larger animals remains subdued. This limitation may be addressed by augmenting the immunogenicity of DNA-based vaccines. In the investigation here, protein expression was enhanced via codon optimization and then mouse cytotoxic T-lymphocyte antigen 4 (CTLA-4) was harnessed as a modulatory adjunct to bind directly to antigen-presenting cells. Further, the study evaluated the immunogenicity of two variants of the hemagglutinin (HA) antigen, i.e. the full-length and the C-terminal deletion versions. The study findings revealed that the codon-optimized HA gene (pcHA) led to increased protein synthesis, as evidenced by elevated mRNA levels. Codon optimization also significantly bolstered both cellular and humoral immune responses. In cytokine assays, all plasmid constructs, particularly pCTLA4-cHA, induced robust interferon (IFN)-γ production, while interleukin (IL)-4 levels remained uniformly non-significant. Mice immunized with pcHA displayed an augmented presence of IFNγ+ T-cells, underscoring the enhanced potency of the codon-optimized HA vaccine. Contrarily, CTLA-4-fused DNA vaccines did not significantly amplify the immune response.

Sero-prevalence and Associated Factors of Major Respiratory Diseases (Avian Influenza, Newcastle Disease, Infectious Bronchitis, and Mycoplasma Gallisepticum) in Layers Farms in Dakar and Thiès, Senegal

Purpose: This study aimed to identify associated factors and the prevalence of major avian respiratory diseases, including Mycoplasma gallisepticum, Influenza H9, Infectious Bronchitis (IB), and Newcastle disease in poultry farms in the Dakar and Thiès regions of Senegal. Methodology:A cross-sectional observational study was conducted on purposively selected farms with over 1000 birds exhibiting respiratory symptoms. Blood samples (400) were collected for serological analysis, and post-mortem examinations were performed to assess disease prevalence. Additionally, data on biosecurity, vaccination, medication practices, general management, and farm infrastructure were obtained through direct observation. Student t-tests were used to analyze the association between different farming practices and respiratory infections. Findings: The results indicated that proximity to neighboring farms, non-compliant buildings, mixed-age groups, and lack of farmer training were associated with respiratory diseases in the surveyed farms. Serological analysis revealed a high prevalence of Mycoplasma gallisepticum and Influenza H9, each detected in 50% of the farms. Infectious Bronchitis was found in 40% of the farms, while Newcastle disease was detected in 35%. Co-infections were common, with the combination of H9 influenza and Mycoplasma gallisepticum being the most prevalent (33%). Unique Contribution to Theory, Practice and Policy: The study emphasizes the need for targeted interventions, including improved biosecurity measures, vaccination strategies, and farmer training, to control respiratory infections. Strengthening biosecurity protocols and enhancing farmer education will help reduce disease.

Neu5Gc binding loss of subtype H7 influenza A virus facilitates adaptation to gallinaceous poultry following transmission from waterbirds.

Between 2013 and 2018, the novel A/Anhui/1/2013 (AH/13)-lineage H7N9 virus caused at least five waves of outbreaks in humans, totaling 1,567 confirmed human cases in China. Surveillance data indicated a disproportionate distribution of poultry infected with this AH/13-lineage virus, and laboratory experiments demonstrated that this virus can efficiently spread among chickens but not among Pekin ducks. The underlying mechanism of this selective transmission remains unclear. In this study, we demonstrated the absence of Neu5Gc expression in chickens across all respiratory and gastrointestinal tissues. However, Neu5Gc expression varied among different duck species and even within the tissues of the same species. The AH/13-lineage viruses exclusively bind to acetylneuraminic acid (Neu5Ac), in contrast to wild waterbird H7 viruses that bind both Neu5Ac and N-glycolylneuraminic acid (Neu5Gc). The level of Neu5Gc expression influences H7 virus replication and facilitates adaptive mutations in these viruses. In summary, our findings highlight the critical role of Neu5Gc in affecting the host range and interspecies transmission dynamics of H7 viruses among avian species.IMPORTANCEMigratory waterfowl, gulls, and shorebirds are natural reservoirs for influenza A viruses (IAVs) that can occasionally spill over to domestic poultry, and ultimately humans. This study showed wild-type H7 IAVs from waterbirds initially bind to glycan receptors terminated with N-acetylneuraminic acid (Neu5Ac) or N-glycolylneuraminic acid (Neu5Gc). However, after enzootic transmission in chickens, the viruses exclusively bind to Neu5Ac. The absence of Neu5Gc expression in gallinaceous poultry, particularly chickens, exerts selective pressure, shaping IAV populations, and promoting the acquisition of adaptive amino acid substitutions in the hemagglutinin protein. This results in the loss of Neu5Gc binding and an increase in virus transmissibility in gallinaceous poultry, particularly chickens. Consequently, the transmission capability of these poultry-adapted H7 IAVs in wild water birds decreases. Timely intervention, such as stamping out, may help reduce virus adaptation to domestic chicken populations and lower the risk of enzootic outbreaks, including those caused by IAVs exhibiting high pathogenicity.

Development of a dual-component biosensor for rapid and sensitive detection of influenza H7 and H5 subtypes

The outbreak of highly pathogenic influenza virus subtypes, such as H7 and H5, presents a significant global health challenge, necessitating the development of rapid and sensitive diagnostic methods. In this study, we have developed a novel dual-component biosensor assembly, each component of which incorporates an antibody fused with a nano-luciferase subunit. Our results demonstrate the effectiveness of this biosensor in enabling the rapid and sensitive detection of influenza H7 and other subtypes. Additionally, we successfully applied the biosensor in paper-based assay and lateral flow assay formats, expanding its versatility and potential for field-deployable applications. Notably, we achieved effective detection of the H7N9 virus using this biosensor. Furthermore, we designed and optimized a dedicated biosensor to the sensitive detection of the influenza H5 subtype. Collectively, our findings underscore the significant potential of this dual-component biosensor assembly as a valuable and versatile tool for accurate and timely diagnosis of influenza virus infections, promising to advance the field of influenza diagnostics and contribute to outbreak management and surveillance efforts.

Collaborative wildlife disease outbreak investigation and response at Bells Swamp Victoria, February 2023.

In February 2023, a report of morbidity and mortality in waterbirds triggered a collaborative regional wildlife disease outbreak investigation and response, led by Parks Victoria. Triage, rehabilitation and diagnosis of sick and dead birds were undertaken by Zoos Victoria (ZV), Agriculture Victoria, Vets for Compassion, Wildlife Victoria and Melbourne Veterinary School (MVS). The field response focused on collection of sick and dead birds for wildlife welfare, for diagnosis, and to reduce environmental contamination. Botulism was suspected, based on clinical signs and lack of significant gross pathology, and this diagnosis was confirmed by PCR testing. Low pathogenicity avian influenza (LPAI) viruses non H5 or H7 were detected in two birds and ruled out in all in others tested. These incidental, non-clinical LPAI detections are considered part of the natural wild bird virus community in Australia. A number of elements contributed to the collaborative effort. Regional individuals had the necessary connections for reporting, collecting and transporting birds. There was rapid determination by the Victorian Department of Energy, Environment and Climate Action (DEECA) that Parks Victoria, as the land managers, should lead the response. Zoos Victoria provided capacity and expertise in wildlife triage and rehabilitation, and Agriculture Victoria, ZV and MVS were responsible for veterinary management of the response and diagnosis. Field investigation and response were conducted by Parks Victoria, Agriculture Victoria, MVS and veterinary teams from Vets for Compassion and Wildlife Victoria. Wildlife Health Australia (WHA) provided guidance and information, approved National Significant Disease Investigation Program funding and captured the event in the national wildlife health information database. Communication and media were important for community understanding of the event.

Deep mutational scanning of H5 hemagglutinin to inform influenza virus surveillance.

H5 influenza is a potential pandemic threat. Previous studies have identified molecular phenotypes of the viral hemagglutinin (HA) protein that contribute to pandemic risk, including cell entry, receptor preference, HA stability, and reduced neutralization by polyclonal sera. Here we use pseudovirus deep mutational scanning to measure how all mutations to a clade 2.3.4.4b H5 HA affect each phenotype. We identify mutations that allow HA to better bind a2-6-linked sialic acids, and show that some viruses already carry mutations that stabilize HA. We also identify recent viral strains with reduced neutralization to sera elicited by candidate vaccine virus. Overall, the systematic nature of deep mutational scanning combined with the safety of pseudoviruses enables comprehensive characterization of mutations to inform surveillance of H5 influenza.

Role of miRNA in Highly Pathogenic H5 Avian Influenza Virus Infection: An Emphasis on Cellular and Chicken Models.

The avian influenza virus, particularly the H5N1 strain, poses a significant and ongoing threat to both human and animal health. Recent outbreaks have affected domestic and wild birds on a massive scale, raising concerns about the virus' spread to mammals. This review focuses on the critical role of microRNAs (miRNAs) in modulating pro-inflammatory signaling pathways during the pathogenesis of influenza A virus (IAV), with an emphasis on highly pathogenic avian influenza (HPAI) H5 viral infections. Current research indicates that miRNAs play a significant role in HPAI H5 infections, influencing various aspects of the disease process. This review aims to synthesize recent findings on the impact of different miRNAs on immune function, viral cytopathogenicity, and respiratory viral replication. Understanding these mechanisms is essential for developing new therapeutic strategies to combat avian influenza and mitigate its effects on both human and animal populations.