Phylogeographic Dynamics of H9N2 Avian Influenza Viruses in Tunisia.

Avian influenza virus subtype H9N2 is endemic in commercial poultry in Tunisia. This subtype affects poultry and wild birds in Tunisia and poses a potential zoonotic risk. Tunisian H9N2 strains carry, in their hemagglutinins, the human-like marker 226 L that is most influential in avian-to-human viral transmission. For a better understanding of how ecological aspects of the H9N2 virus and its circulation in poultry, migratory birds and environment shapes the spread of the dissemination of H9N2 in Tunisia, herein, we investigate the epidemiological, evolutionary and zoonotic potential of seven H9N2 poultry isolates and sequence their whole genome. Phylogeographic and phylodymanic analysis were used to examine viral spread within and among wild birds, poultry and environment at geographical scales. Genetic evolution results showed that the eight gene sequences of Tunisian H9N2 AIV were characterized by molecular markers involved with virulence and mammalian infections. The geographical distribution of avian influenza virus appears as a network interconnecting countries in Europe, Asia, North Africa and West Africa. The spatiotemporal dynamics analysis showed that the H9N2 virus was transmitted from Tunisia to neighboring countries notably Libya and Algeria. Interestingly, this study also revealed, for the first time, that there was a virus transmission between Tunisia and Morocco. Bayesian analysis showed exchanges between H9N2 strains of Tunisia and those of the Middle Eastern countries, analysis of host traits showed that duck, wild birds and environment were ancestry related to chicken. The subtypes phylodynamic showed that PB1 segment was under multiple inter-subtype reassortment events with H10N7, H12N5, H5N2 and H6N1 and that PB2 was also a subject of inter-subtype reassortment with H10N4.

Molecular and Antigenic Characterization of Avian H9N2 Viruses in Southern China.

The H9N2 subtype avian influenza virus (AIV) has become endemic in poultry globally; however due to its low pathogenicity, it is not under primary surveillance and control in many countries. Recent reports of human infection caused by H9N2 AIV has increased public concern. This study investigated the genetic and antigenic characteristics of H9N2 AIV isolated from local markets in nine provinces in Southern China from 2013 to 2018. We detected an increasing annual isolation rate of H9N2 AIV. Phylogenetic analyses of hemagglutinin (HA) genes suggests that isolated strains were rooted in BJ94 lineage but have evolved into new subgroups (II and III), which derived from subgroup I. The estimated substitution rate of the subgroup III strains was 6.23 × 10-3 substitutions/site/year, which was 1.5-fold faster than that of the average H9N2 HA rate (3.95 × 10-3 substitutions/site/year). Based on the antigenic distances, subgroup II and III strains resulted in two clear antigenic clusters 2 and 3, separated from the vaccine strain F98, cluster 1. New antigenic properties of subgroup III viruses were associated with 11 amino acid changes in the HA protein, suggesting antigenic drift in H9N2 viruses. Our phylogenetic and antigenic analyses of the H9N2 strains circulating in local markets in Southern China provide new insights on the antigenic diversification of H9N2 viruses. IMPORTANCE The H9N2 low pathogenicity avian influenza (LPAI) virus has become endemic in poultry globally. In several Asian countries, vaccination against H9N2 avian influenza virus (AIV) was approved to reduce economic losses in the poultry industry. However, surveillance programs initiated after the introduction of vaccination identified the persistence of H9N2 AIV in poultry (especially in chicken in South Korea and China). Recent reports of human infection caused by H9N2 AIV has increased public concern. Surveillance of H9N2 circulating in poultry in the fields or markets was essential to update the vaccination strategies. This study investigated the genetic and antigenic characteristics of H9N2 AIVs isolated from local markets in nine provinces in Southern China from 2013 to 2018. The discovery of mutations in the hemagglutinin (HA) gene that result in antigenic changes provides a baseline reference for evolutionary studies of H9N2 viruses and vaccination strategies in poultry.

Emergence, prevalence, and evolution of H5N8 avian influenza viruses in central China, 2020.

Highly pathogenic influenza A(H5N8) viruses have caused several worldwide outbreaks in birds and are able cross the species barrier to infect humans, posing a substantial threat to public health. After the first detection of H5N8 viruses in deceased swans in Inner Mongolia, we performed early warning and active monitoring along swan migration routes in central China. We isolated and sequenced 42 avian influenza viruses, including 40 H5N8 viruses, 1 H5N2 virus, and 1 H9N2 virus, in central China. Our H5N8 viruses isolated in swan stopover sites and wintering grounds showed high nucleotide homologies in the whole genome, revealing a common evolutionary source. Phylogenetic analysis revealed that the H5 viruses of clade 2.3.4.4b prevalent in 2020 have further diverged into two sub-clades: b1 and b2. The phylogeographic analysis also showed that the viruses of sub-clade b2 most likely originated from poultry in Russia. Notably, whooper swans were found to be responsible for the introduction of sub-clade b2 viruses in central China; whooper and tundra swans play a role in viral spread in the Yellow River Basin and the Yangtze River Basin, respectively. Our findings highlight swans as an indicator species for transborder spreading and monitoring of the H5N8 virus.

Airborne Transmission of Avian Origin H9N2 Influenza A Viruses in Mammals.

Influenza A viruses (IAV) are widespread viruses affecting avian and mammalian species worldwide. 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, which circulate endemically in poultry flocks in some regions of the world, have also been associated with cases of zoonotic infections. In this review, we discuss the mammalian transmission of H9N2 and the molecular factors that are thought relevant for this spillover, focusing on the HA segment. Additionally, we discuss factors that have been associated with the ability of these viruses to transmit through the respiratory route in mammalian species. The summarized information shows that minimal amino acid changes in the HA and/or the combination of H9N2 surface genes with internal genes of human influenza viruses are enough for the generation of H9N2 viruses with the ability to transmit via aerosol.

Molecular characterization, receptor binding property, and replication in chickens and mice of H9N2 avian influenza viruses isolated from chickens, peafowls, and wild birds in eastern China.

H9N2 avian influenza viruses are widely prevalent in birds and pose an increasing threat to humans because of their enhanced virulence and transmissibility in mammals. Active surveillance on the prevalence and evolution of H9N2 viruses in different avian hosts will help develop eradication measures. We isolated 16 H9N2 viruses from chickens, green peafowls, and wild birds in eastern China from 2017 to 2019 and characterized their comparative genetic evolution, receptor-binding specificity, antigenic diversity, replication, and transmission in chickens and mice. The phylogenetic analysis indicated that the green peafowl viruses and swan reassortant shared the same ancestor with the poultry H9N2 viruses prevalent in eastern China, while the seven wild bird viruses belonged to wild bird lineage. The chicken, peafowl, and swan H9N2 viruses that belonged to the poultry lineage preferentially recognized α-2, 6-linked sialic acids (human-like receptor), but the wild bird lineage viruses can bind both α-2, 3 (avian-like receptor) and human-like receptor similarly. Interestingly, the H9N2 viruses of poultry lineage replicated well and transmitted efficiently, but the viruses of wild bird lineage replicated and transmitted with low efficiency. Importantly, the H9N2 viruses of poultry lineage replicated in higher titer in mammal cells and mice than the viruses of wild birds lineage. Altogether, our study indicates that co-circulation of the H9N2 viruses in poultry, wild birds, and ornamental birds increased their cross-transmission risk in different birds because of their widespread dissemination.

Double mutations in the H9N2 avian influenza virus PB2 gene act cooperatively to increase viral host adaptation and replication for human infections.

Avian H9N2 influenza viruses in East Asia are genetically diversified and multiple genotypes (A-W) have been established in poultry. Genotype S strains are currently the most prevalent strains, have caused many human infections and pose a public health threat. In this study, human adaptation mutations in the PB2 polymerase in genotype S strains were identified by database screening. Several PB2 double mutations were identified that acted cooperatively to produce higher genotype S virus polymerase activity and replication in human cells than in avian cells and to increase viral growth and virulence in mice. These mutations were chronologically and phylogenetically clustered in a new group within genotype S viruses. Most of the relevant human virus isolates carry the PB2-A588V mutation together with another PB2 mutation (i.e. K526R, E627V or E627K), indicating a host adaptation advantage for these double mutations. The prevalence of PB2 double mutations in human H9N2 virus isolates has also been found in genetically related human H7N9 and H10N8 viruses. These results suggested that PB2 double mutations in viruses in the field acted cooperatively to increase human adaptation of the currently prevalent H9N2 genotype S strains. This may have contributed to the recent surge of H9N2 infections and may be applicable to the human adaptation of several other avian influenza viruses. Our study provides a better understanding of the human adaptation pathways of genetically related H9N2, H7N9 and H10N8 viruses in nature.

Genetic characterization of H9N2 avian influenza virus previously unrecognized in Korea.

In this study, we describe the isolation and characterization of previously unreported Y280-lineage H9N2 viruses from two live bird markets in Korea in June 2020. Genetic analysis revealed that they were distinct from previous H9N2 viruses circulating in Korea and had highest homology to A/chicken/Shandong/1844/2019(H9N2) viruses. Their genetic constellation showed they belonged to genotype S, which is the predominant genotype in China since 2010, where genotype S viruses have infected humans and acted as internal gene donors to H5 and H7 zoonotic influenza viruses. Active surveillance and control measures need to be enhanced to protect the poultry industry and public health.

Detection of novel reassortant H9N2 avian influenza viruses in wild birds in Jiangxi Province, China.

The five avian influenza A/H9N2 viruses isolated from wild birds in Jiangxi, China in 2015 are novel reassortants which most likely evolved from multiple lineages. They shared a high similarity with isolates from poultry, suggesting a frequent contact and continuous viral circulation at the bird-poultry interface. Given the continuous reassortment of H9N2 viruses, it will of substantial importance to implement routine surveillance in wild birds to successfully control avian influenza viruses and better the early warning system of the emerging reassortants with pandemic potential.

Identification of key residues involved in the neuraminidase antigenic variation of H9N2 influenza virus.

Influenza A H9N2 virus causes economic loss to the poultry industry and has likely contributed to the genesis of H5N1 and H7N9 viruses. The neuraminidase (NA) of H9N2 virus, like haemagglutinin, is under antibody selective pressure and may undergo antigenic change; however, its antigenic structure remains to be elucidated. In this study, we used monoclonal antibodies (mAbs) to probe the H9N2 viral NA residues that are key for antibody binding/inhibition. These mAbs fell into three groups based on their binding/inhibition of the NA of H9N2 viruses isolated during 1999-2019: group I only bounded the NA of the early 2000 H9N2 viruses but possessed no neutralizing ability, group II bounded and inhibited the NA of H9N2 viruses isolated before 2012, and group III reacted with most or all tested H9N2 viruses. We showed that NA residue 356 is key for the recognition by group I mAbs, residues 344, 368, 369, and 400 are key for the binding/inhibition of NA by group II antibodies, whereas residues 248, 253, and the 125/296 combination are key for neutralizing antibodies in group III. Our findings highlighted NA antigenic change of the circulating H9N2 viruses, and provided data for a more complete picture of the antigenic structure of H9N2 viral NA.

The adaptability of H9N2 avian influenza A virus to humans: A comparative docking simulation study.

Influenza A virus, the H9N2 subtype, is an avian influenza virus that has long been circulating in the worldwide poultry industry and is occasionally found to be transmissible to humans. Evidence from genomic analysis suggests that H9N2 provides the genes for the H5N1 and H7N9 subtypes, which have been found to infect mammals and pose a threat to human health. However, due to the lack of a structural model of the interaction between H9N2 and host cells, the mechanism of the extensive adaptability and strong transformation capacity of H9N2 is not fully understood. In this paper, we collected 40 representative H9N2 virus samples reported recently, mainly in China and neighboring countries, and investigated the interactions between H9N2 hemagglutinin and the mammalian receptor, the polysaccharide α-2,6-linked lactoseries tetrasaccharide c, at the atomic level using docking simulation tools. We categorized the mutations of studied H9N2 hemagglutinin according to their effects on ligand-binding interactions and the phylogenetic analysis. The calculations indicated that all the studied H9N2 viruses can establish a tight binding with LSTc although the mutations caused a variety of perturbations to the local conformation of the binding pocket. Our calculations suggested that a marginal equilibrium is established between the conservative ligand-receptor interaction and the conformational dynamics of the binding pocket, and it might be this equilibrium that allows the virus to accommodate mutations to adapt to a variety of environments. Our results provided a way to understand the adaptive mechanisms of H9N2 viruses, which may help predict its propensity to spread in mammals.

Historical origins and zoonotic potential of avian influenza virus H9N2 in Tunisia revealed by Bayesian analysis and molecular characterization.

During 2009-2012, several outbreaks of avian influenza virus H9N2 were reported in Tunisian poultry. The circulating strains carried in their hemagglutinins the human-like marker 226L, which is known to be important for avian-to-human viral transmission. To investigate the origins and zoonotic potential of the Tunisian H9N2 viruses, five new isolates were identified during 2012-2016 and their whole genomes were sequenced. Bayesian-based phylogeny showed that the HA, NA, M and NP segments belong to the G1-like lineage. The PB1, PB2, PA and NS segments appeared to have undergone multiple intersubtype reassortments and to be only distantly related to all of the Eurasian lineages (G1-like, Y280-like and Korean-like). The spatiotemporal dynamic of virus spread revealed that the H9N2 virus was transferred to Tunisia from the UAE through Asian and European pathways. As indicated by Bayesian analysis of host traits, ducks and terrestrial birds played an important role in virus transmission to Tunisia. The subtype phylodynamics showed that the history of the PB1 and PB2 segments was marked by intersubtype reassortments with H4N6, H10N4 and H2N2 subtypes. Most of these transitions between locations, hosts and subtypes were statistically supported (BF > 3) and not influenced by sampling bias. Evidence of genetic evolution was observed in the predicted amino acid sequences of the viral proteins of recent Tunisian H9N2 viruses, which were characterized by the acquisition of new mutations involved in virus adaptation to avian and mammalian hosts and amantadine resistance. This study is the first comprehensive analysis of the evolutionary history of Tunisian H9N2 viruses and highlights the zoonotic risk associated with their circulation in poultry, indicating the need for continuous surveillance of their molecular evolution.

New molecular evolutionary characteristics of H9N2 avian influenza virus in Guangdong Province, China.

To understand the evolution of H9N2 avian influenza virus genotype and its molecular evolution rate, we systematically analyzed 72 H9N2 avian influenza virus sequences isolated from Guangdong province from 2014 to 2018. We found three genotypes (G57, G68, and G118) of the H9N2 avian influenza virus, of which G118 is a newly discovered genotype and G57 is the dominant genotype. The internal gene cassette of the G57 genotype H9N2 avian influenza virus is a stable combination that can easily transport internal genes to other novel avian influenza viruses, and the internal gene cassettes of the G68 and G118 are identical to those of G57.In addition, we estimated the nucleotide substitution rate of the HA and NA genes of the H9N2 influenza virus from 2014 to 2018.The nucleotide substitution rate of HA and NA genes showed an upward trend in 2015 and 2016. In the past two years, H9N2 avian influenza virus recombination has produced genotype G68, which disappeared in 2014 for one year. And very coincidentally, in 2015, there was a new genotype G118. We observed that the emergence of new genotypes was accompanied by a slight increase in overall nucleotide substitution rate. Therefore we hypothesize that the emergence of new genotypes could accelerate the molecular evolution rate of genes. Our research shows that the H9N2 avian influenza virus in Guangdong province has been undergoing intense evolution, demonstrating the need to strengthen influenza surveillance in the region.

Genetic characterization and pathogenesis of the first H9N2 low pathogenic avian influenza viruses isolated from chickens in Kenyan live bird markets.

Poultry production plays an important role in the economy and livelihoods of rural households in Kenya. As part of a surveillance program, avian influenza virus (AIV)-specific real-time RT-PCR (RRT-PCR) was used to screen 282 oropharyngeal swabs collected from chickens at six live bird markets (LBMs) and 33 backyard poultry farms in Kenya and 8 positive samples were detected. Virus was isolated in eggs from five samples, sequenced, and identified as H9N2 low pathogenic AIV (LPAIV) G1 lineage, with highest nucleotide sequence identity (98.6-99.9%) to a 2017 Ugandan H9N2 isolate. The H9N2 contained molecular markers for mammalian receptor specificity, implying their zoonotic potential. Virus pathogenesis and transmissibility was assessed by inoculating low and medium virus doses of a representative Kenyan H9N2 LPAIV isolate into experimental chickens and exposing them to naïve uninfected chickens at 2 -days post inoculation (dpi). Virus shedding was determined at 2/4/7 dpi and 2/5 days post placement (dpp), and seroconversion determined at 14 dpi/12 dpp. None of the directly-inoculated or contact birds exhibited any mortality or clinical disease signs. All directly-inoculated birds in the low dose group shed virus during the experiment, while only one contact bird shed virus at 2 dpp. Only two directly-inoculated birds that shed high virus titers seroconverted in that group. All birds in the medium dose group shed virus at 4/7 dpi and at 5 dpp, and they all seroconverted at 12/14 dpp. This is the first reported detection of H9N2 LPAIV from Kenya and it was shown to be infectious and transmissible in chickens by direct contact and represents a new disease threat to poultry and potentially to people.

First report of human infection with avian influenza A(H9N2) virus in Oman: The need for a One Health approach.

Following the detection of the first human case of avian influenza A subtype H9N2 in 1998, more than 40 cases were diagnosed worldwide. However, the spread of the virus has been more remarkable and significant in global poultry populations, causing notable economic losses despite its low pathogenicity. Many surveillance studies and activities conducted in several countries have shown the predominance of this virus subtype. We present the case of a 14-month-old female in Oman with an A(H9N2) virus infection. This is the first human case of A(H9N2) reported from Oman and the Gulf Cooperation Countries, and Oman is the second country outside of southern and eastern Asia to report a case (cases have also been detected in Egypt). The patient had bronchial asthma and presented with a high-grade temperature and symptoms of lower respiratory tract infection that necessitated admission to a high dependency unit in a tertiary care hospital. It is of urgency that a multisector One Health approach be established to combat the threat of avian influenza at the animal-human interface. In addition to enhancements of surveillance and control in poultry, there is a need to develop screening and preventive programs for high-risk occupations.

H9 Influenza Viruses: An Emerging Challenge.

Influenza A viruses (IAVs) of the H9 subtype are enzootic in Asia, the Middle East, and parts of North and Central Africa, where they cause significant economic losses to the poultry industry. Of note, some strains of H9N2 viruses have been linked to zoonotic episodes of mild respiratory diseases. Because of the threat posed by H9N2 viruses to poultry and human health, these viruses are considered of pandemic concern by the World Health Organization (WHO). H9N2 IAVs continue to diversify into multiple antigenically and phylogenetically distinct lineages that can further promote the emergence of strains with pandemic potential. Somewhat neglected compared with the H5 and H7 subtypes, there are numerous indicators that H9N2 viruses could be involved directly or indirectly in the emergence of the next influenza pandemic. The goal of this work is to discuss the state of knowledge on H9N2 IAVs and to provide an update on the contemporary global situation.

Molecular evolution and amino acid characteristics of newly isolated H9N2 avian influenza viruses from Liaoning Province, China.

H9N2 is widespread among poultry and humans. Though this subtype is not lethal to either species, it can cause considerable financial losses for farmers and threaten human health. In this study, 10 new H9N2 avian influenza viruses (AIVs) produced by reassortment were isolated from domestic birds in Liaoning Province between March 2012 and October 2014. Nucleotide sequence comparisons indicate that the internal genes of one of these strains are highly similar to those of human H7N9 viruses. Amino acid substitutions and deletions occurred in the HA and NA proteins separately, indicating that all 10 of these isolates may have an enhanced ability to infect mammals. A cross-hemagglutinin inhibition assay conducted with two vaccine strains that are broadly used in China suggests that antisera against vaccine candidates cannot completely inhibit the new isolates. Two of the 10 newly isolated viruses could replicate in respiratory organs of infected BALB/c mice without adaption, suggesting that these isolates can potentially infect mammals. The continued surveillance of poultry is important to provide early warning and control of AIV outbreaks. Our results highlight the high genetic diversity of AIV and the need for more extensive AIV surveillance.

Isolation and Characterization of Avian Influenza H9N2 Viruses from Different Avian Species in Pakistan 2016-17.

Avian influenza (AI) virus (AIV) subtype H9N2 continues to cause significant outbreaks among commercial and backyard poultry in Pakistan. Despite this, the characterization of H9N2 viruses in avian hosts other than chickens in Pakistan has not been thoroughly investigated. In this study, 12 low pathogenicity avian influenza viruses subtype H9N2 were isolated from peacocks (n = 4), ducks (n = 4), pheasants (n = 2), geese (n = 1), and black swans (n = 1) in Pakistan during 2016 and were characterized on the basis of the hemagglutinin (HA) and neuraminidase genes. All of the viruses possessed an amino acid substitution Q226L in the receptor-binding site of the HA protein, which is known to contribute to increased viral replication and virulence in mammals. In addition, phylogenetic studies showed that these H9N2 AIVs belonged to the Middle East B genetic group of sublineage G1 and were very similar to viruses isolated from an outbreak in chickens in Pakistan in 2017. This demonstrates an epidemiologic link between poultry and other avian species, which is a fact to consider in future H9N2 disease management programs.

Nota de investigación ­ Aplicación in ovo y al primer día de edad de una vacuna viva contra el virus de la enfermedad infecciosa de la bolsa en pollos de engorde comerciales. La enfermedad infecciosa de la bolsa (IBD) es una enfermedad económicamente importante de pollos jóvenes causada por un Avibirnavirus, el virus de la enfermedad infecciosa de la bolsa (IBDV). El virus causal es altamente resistente a los ambientes avícolas y la vacunación es la medida más efectiva para el control de esta enfermedad. Sin embargo, la presunta neutralización de las cepas altamente atenuadas por los anticuerpos maternos y la supuesta virulencia de las cepas parcialmente atenuadas ha limitado la implementación de cepas de vacunas vivas convencionales contra la enfermedad de Gumboro en pollitos antes o después de la eclosión. Sin embargo, los datos preliminares han generado dudas sobre la validez de este dogma prevaleciente. Para analizar la posible aplicación de una cepa de vacuna viva intermedia plus del virus de Gumboro, cepa MB-1, en embriones de pollo con inmunidad materna y a pollos de un día de edad, se realizaron cuatro ensayos de campo a gran escala en distintos lugares del mundo. Los cuatro ensayos midieron la seguridad relativa, los parámetros de inmunización para Gumboro y los rendimientos de producción de MB-1 frente a las vacunas de Gumboro con complejos inmunes establecidas en una variedad de sistemas comerciales de engorde. El desempeño general de la salud y la producción en los cuatro ensayos ha sido similar o mejor en los grupos con la cepa MB-1. Los resultados desafían la noción prevaleciente de que las cepas vivas de del virus de la enfermedad infecciosa de la bolsa pueden neutralizarse o sobrepasar la inmunidad materna e inducir daño permanente a la respuesta inmune de los pollos de engorde jóvenes. Se ha observado un fenómeno de replicación retardada después de la administración parenteral de la cepa de vacuna viva contra el virus de la enfermedad de Gumboro, sin embargo, este mecanismo de replicación retardada aún no se ha dilucidado. Los resultados de este estudio justifican una mayor investigación de las cepas de vacunas vivas convencionales contra la enfermedad de Gumboro como una alternativa para la inmunización activa de pollos de engorde antes y después de la eclosión.

Genetic Characteristics and Pathogenicity Analysis in Chickens and Mice of Three H9N2 Avian Influenza Viruses.

H9N2 avian influenza is a remarkable disease that has circulated in domestic poultry in large regions of China and posed a serious threat to the poultry industry. The H9N2 virus can not only infect mammals directly, but also provide gene segments to generate novel, but lethal human reassortants. Therefore, it is important to study the evolution, pathogenicity, and transmission of the H9N2 virus. In this study, three H9N2 viruses isolated from chickens in different layer farms were identified. Phylogenetic analysis revealed that these H9N2 viruses were all multiple genotype reassortants, with genes originating from Y280-like, F/98-like, and G1-like viruses. Animal studies indicated that the AV1535 and AV1548 viruses replicated efficiently in the lungs, tracheas, spleens, kidneys, and brains of chickens; the viruses shed for at least 11 days post-inoculation (DPI) and were transmitted efficiently among contact chickens. The AV1534 virus replicated poorly in chickens, shed for 7 DPI, and were not transmitted efficiently among contact chickens. The AV1534 virus replicated well in mice lungs and caused about 2% weight loss. The AV1535 and AV1548 viruses were not able to replicate in the lungs of mice. Our results indicate that we should pay attention to H9N2 avian influenza virus surveillance in poultry and changes in the pathogenicity of them to mammals.

Laboratory-Confirmed Avian Influenza A(H9N2) Virus Infection, India, 2019.

A 17-month-old boy in India with severe acute respiratory infection was laboratory confirmed to have avian influenza A(H9N2) virus infection. Complete genome analysis of the strain indicated a mixed lineage of G1 and H7N3. The strain also was found to be susceptible to adamantanes and neuraminidase inhibitors.

Inferring host roles in bayesian phylodynamics of global avian influenza A virus H9N2.

Role of avian hosts in shaping persistence, evolution, and dispersal of global low pathogenic avian influenza virus (LPAIV) H9N2 remains uncertain. Under Bayesian Markov Chain Monte Carlo framework, we used the discrete trait analysis (DTA) to reconstruct host and location switches in the evolutionary history of global H9N2 given hemagglutinin gene sequences from 18 countries/regions between 1976 and 2018. We employed generalized linear models (GLMs) to inform virus migration rates by empirical predictors. Global H9N2 isolates were mostly sampled from domestic Phasianidae in low- and middle-income countries with poor bio-security. Anatidae was inferred as the ancestral source from which the virus spread to domestic waterfowl, and later to domestic Phasianidae who have become the dominant host to sustain the virus, especially in Asia. Poultry trade was a well-supported driver to H9N2 spread across countries/regions. Strict bio-security and separation between wild and domestic poultry can be used to mitigate virus spread.