RESUMO
We have demonstrated for the first time a comprehensive evolutionary analysis of the Mexican lineage H5N2 avian influenza virus (AIV) using complete genome sequences (n = 189), from its first isolation in 1993 until 2019. Our study showed that the Mexican lineage H5N2 AIV originated from the North American wild bird gene pool viruses around 1990 and is currently circulating in poultry populations of Mexico, the Dominican Republic, and Taiwan. Since the implementation of vaccination in 1995, the highly pathogenic AIV (HPAIV) H5N2 virus was eradicated from Mexican poultry in mid-1995. However, the low pathogenic AIV (LPAIV) H5N2 virus has continued to circulate in domestic poultry populations in Mexico, eventually evolving into five distinct clades. In the current study, we demonstrate that the evolution of Mexican lineage H5N2 AIVs involves gene reassortments and mutations gained over time. The current circulating Mexican lineage H5N2 AIVs are classified as LPAIV based on the amino acid sequences of the hemagglutinin (HA) protein cleavage site motif as well as the results of the intravenous pathogenicity index (IVPI). The immune pressure from vaccinations most likely has played a significant role in the positive selection of antigenic drift mutants within the Mexican H5N2 AIVs. Most of the identified substitutions in these viruses are located on the critical antigenic residues of the HA protein and as a result, might have contributed to vaccine failures. This study highlights and stresses the need for vaccine updates while emphasizing the importance of continued molecular monitoring of the HA protein for its antigenic changes compared to the vaccines used.
Assuntos
Vírus da Influenza A Subtipo H5N2 , Vírus da Influenza A , Influenza Aviária , Animais , Galinhas , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Vírus da Influenza A/genética , México , Filogenia , Aves DomésticasRESUMO
The Mexican lineage H5N2 low pathogenic avian influenza viruses (LPAIVs) were first detected in 1994 and mutated to highly pathogenic avian influenza viruses (HPAIVs) in 1994-1995 causing widespread outbreaks in poultry. By using vaccination and other control measures, the HPAIVs were eradicated but the LPAIVs continued circulating in Mexico and spread to several other countries. To get better resolution of the phylogenetics of this virus, the full genome sequences of 44 H5N2 LPAIVs isolated from 1994 to 2011, and 6 detected in 2017 and 2019, were analysed. Phylogenetic incongruence demonstrated genetic reassortment between two separate groups of the Mexican lineage H5N2 viruses between 2005 and 2010. Moreover, the recent H5N2 viruses reassorted with previously unidentified avian influenza viruses. Bayesian phylogeographic results suggested that mechanical transmission involving human activity is the most probable cause of the virus spillover to Central American, Caribbean, and East Asian countries. Increased infectivity and transmission of a 2011 H5N2 LPAIV in chickens compared to a 1994 virus demonstrates improved adaptation to chickens, while low virus shedding, and limited contact transmission was observed in mallards with the same 2011 virus. The sporadic increase in basic amino acids in the HA cleavage site, changes in potential N-glycosylation sites in the HA, and truncations of PB1-F2 should be further examined in relation to the increased infectivity and transmission in poultry. The genetic changes that occur as this lineage of H5N2 LPAIVs continues circulating in poultry is concerning not only because of the effect of these changes on vaccination efficacy, but also because of the potential of the viruses to mutate to the highly pathogenic form. Continued vigilance and surveillance efforts, and the pathogenic and genetic characterization of circulating viruses, are required for the effective control of this virus.
Assuntos
Vírus da Influenza A Subtipo H5N2 , Vírus da Influenza A , Influenza Aviária , Aminoácidos Básicos/genética , Animais , Teorema de Bayes , Galinhas , Humanos , Vírus da Influenza A Subtipo H5N2/genética , Vírus da Influenza A/genética , México/epidemiologia , Filogenia , Aves DomésticasRESUMO
Influenza A virus (IAV) outbreaks constitute a constant threat to public health and pose a remarkable impact on socio-economic systems worldwide. Interactions between wild and domestic birds, humans and swine can lead to spillover events. Backyard livestock systems in proximity to wetlands represent high-risk areas for viral spread. However, some gaps remain in our knowledge of IAV transmission at the wildlife-livestock interface in Mexico. Hence, the study aimed at molecular identification and phylogenetic characterization of IAV in the wild duck-backyard livestock interface at a wetland of Mexico. A total of 875 animals were tested by real-time RT-PCR (qRT-PCR). We detected IAV in 3.68% of the wild ducks sampled during the winter season 2016-2017. Nonetheless, the samples obtained from backyard poultry and swine tested negative. The highest IAV frequency (11.10%) was found in the Mexican duck (Anas diazi). Subtypes H1N1, H3N2 and H5N2 were detected. Phylogenetic analyses revealed that IAV detected in wild birds from the Lerma wetlands was mostly related to swine and poultry IAV strains previously isolated in the United States and Mexico. Except, the UIFMVZ377/H5N2 related to North American waterbirds. In conclusion, the co-circulation of three IAV subtypes in wild ducks close to backyard farms in Mexico, as well as the local identification of influenza viruses genetically related to Mexican and North American IAV strains, highlights the importance of the Lerma marshes for influenza surveillance given the close interaction among wild birds, poultry, pigs and humans.
Assuntos
Vírus da Influenza A Subtipo H1N1 , Vírus da Influenza A Subtipo H5N2 , Vírus da Influenza A , Influenza Aviária , Doenças dos Suínos , Animais , Animais Selvagens , Vírus da Influenza A Subtipo H3N2 , Vírus da Influenza A/genética , Influenza Aviária/epidemiologia , Gado , México/epidemiologia , Filogenia , Suínos , Doenças dos Suínos/epidemiologia , Estados UnidosRESUMO
Low pathogenicity avian influenza (H5N2) virus was detected in poultry in the Dominican Republic in 2007 and re-emerged in 2017. Whole-genome sequencing and phylogenetic analysis show introduction of an H5N2 virus lineage from Mexico into poultry in the Dominican Republic, then divergence into 3 distinct genetic subgroups during 2007-2019.
Assuntos
Vírus da Influenza A Subtipo H5N2 , Influenza Aviária , Doenças das Aves Domésticas , Animais , República Dominicana/epidemiologia , Influenza Aviária/epidemiologia , México , Filogenia , Aves Domésticas , VirulênciaRESUMO
Neuraminidase (NA) of influenza viruses enables the virus to access the cell membrane. It degrades the sialic acid contained in extracellular mucin. Later, it is responsible for releasing newly formed virions from the membrane of infected cells. Both processes become key functions within the viral cycle. Therefore, it is a therapeutic target for research of the new antiviral agents. Structure-activity relationships studies have revealed which are the important functional groups for the receptor-ligand interaction. Influenza virus type A NA activity was inhibited by five scaffolds without structural resemblance to sialic acid. Intending small organic compound repositioning along with drug repurposing, this study combined in silico simulations of ligand docking into the known binding site of NA, along with in vitro bioassays. The five proposed scaffolds are N-acetylphenylalanylmethionine, propanoic 3-[(2,5-dimethylphenyl) carbamoyl]-2-(piperazin-1-yl) acid, 3-(propylaminosulfonyl)-4-chlorobenzoic acid, ascorbic acid (vitamin C), and 4-(dipropylsulfamoyl) benzoic acid (probenecid). Their half maximal inhibitory concentration (IC50) was determined through fluorometry. An acidic reagent 2'-O-(4-methylumbelliferyl)-α-dN-acetylneuraminic acid (MUNANA) was used as substrate for viruses of human influenza H1N1 or avian influenza H5N2. Inhibition was observed in millimolar ranges in a concentration-dependent manner. The IC50 values of the five proposed scaffolds ranged from 6.4 to 73 mM. The values reflect a significant affinity difference with respect to the reference drug zanamivir (p < 0.001). Two compounds (N-acetyl dipeptide and 4-substituted benzoic acid) clearly showed competitive mechanisms, whereas ascorbic acid reflected non-competitive kinetics. The five small organic molecules constitute five different scaffolds with moderate NA affinities. They are proposed as lead compounds for developing new NA inhibitors which are not analogous to sialic acid.
Assuntos
Inibidores Enzimáticos/química , Vírus da Influenza A Subtipo H1N1/enzimologia , Vírus da Influenza A Subtipo H5N2/enzimologia , Neuraminidase/antagonistas & inibidores , Antivirais/química , Antivirais/metabolismo , Ácido Benzoico/química , Ácido Benzoico/metabolismo , Sítios de Ligação , Ligação Competitiva , Inibidores Enzimáticos/metabolismo , Humanos , Cinética , Ligantes , Simulação de Acoplamento Molecular , Ácido N-Acetilneuramínico/química , Neuraminidase/metabolismo , Relação Estrutura-Atividade , Zanamivir/química , Zanamivir/metabolismoRESUMO
Congregation of different migratory and resident bird species on aquatic ecosystems during winter migration increases contact rates and enhances influenza A virus (IAV) transmission. However, scarce research has been focused on the resident bird's contribution to the viral ecology at a local scale. The Mexican duck (Anas diazi) is an endemic endangered anatid from Mexico. This resident species shares aquatic habitats with migratory birds in the wetlands of Central Mexico. Therefore, here we describe the phylogenetic analysis of an IAV (A/Mexican duck/EstadodeMexico; Lerma/UIFMVZ377/2016(H5N2)) isolated in this species, during spatiotemporal concurrence with migratory anatids in the winter season. All eight gene sequences were obtained by nextgeneration sequencing. Maximum Likelihood trees were constructed using MEGA-X, with General Time Reversible + Invariant (GTR+I), Subtree Pruning and Regrafting (SPR) heuristic method, and 1000 bootstrap replicates. Similarities with six different IAV subtypes were observed through a BLAST search: H6N5, H7N7, H5N2, H4N6, H9N2, and H11N9, detected in wild ducks during 2015 in the Pacific, Central and Mississippi flyways stop sites across the United States of America and Canada. The molecular identification of this reassortant H5N2 IAV highlights the importance of resident species as a reservoir host and its potential participation in the maintenance and transmission of IAV in wetlands surrounded by rural areas.
Assuntos
Patos/virologia , Vírus da Influenza A Subtipo H5N2/genética , Influenza Aviária/virologia , Filogenia , Animais , Influenza Aviária/epidemiologia , México/epidemiologiaRESUMO
Influenza, a zoonosis caused by various influenza A virus subtypes, affects a wide range of species, including humans. Pig cells express both sialyl-α-2,3-Gal and sialyl-α-2,6-Gal receptors, which make them susceptible to infection by avian and human viruses, respectively. To date, it is not known whether wild pigs in Mexico are affected by influenza virus subtypes, nor whether this would make them a potential risk of influenza transmission to humans. In this work, 61 hogs from two municipalities in Campeche, Mexico, were sampled. Hemagglutination inhibition assays were performed in 61 serum samples, and positive results were found for human H1N1 (11.47%), swine H1N1 (8.19%), and avian H5N2 (1.63%) virus variants. qRT-PCR assays were performed on the nasal swab, tracheal, and lung samples, and 19.67% of all hogs were positive to these assays. An avian H5N2 virus, first reported in 1994, was identified by sequencing. Our results demonstrate that wild pigs are participating in the exposure, transmission, maintenance, and possible diversification of influenza viruses in fragmented habitats, highlighting the synanthropic behavior of this species, which has been poorly studied in Mexico.
Assuntos
Vírus da Influenza A/isolamento & purificação , Influenza Humana/transmissão , Influenza Humana/virologia , Infecções por Orthomyxoviridae/veterinária , Doenças dos Suínos/virologia , Animais , Animais Selvagens/virologia , Testes de Inibição da Hemaglutinação , Humanos , Vírus da Influenza A Subtipo H1N1/classificação , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H5N2/classificação , Vírus da Influenza A Subtipo H5N2/genética , Vírus da Influenza A Subtipo H5N2/isolamento & purificação , Vírus da Influenza A/classificação , Vírus da Influenza A/genética , Influenza Humana/epidemiologia , Pulmão/patologia , Pulmão/virologia , México/epidemiologia , Infecções por Orthomyxoviridae/epidemiologia , Infecções por Orthomyxoviridae/patologia , Infecções por Orthomyxoviridae/virologia , Suínos , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/patologia , Doenças dos Suínos/transmissão , Traqueia/patologia , Traqueia/virologia , Zoonoses/epidemiologia , Zoonoses/transmissão , Zoonoses/virologiaRESUMO
Despite decades of vaccination, surveillance, and biosecurity measures, H5N2 low pathogenicity avian influenza (LPAI) virus infections continue in Mexico and neighboring countries. One explanation for tenacity of H5N2 LPAI in Mexico is the antigenic divergence of circulating field viruses compared to licensed vaccines due to antigenic drift. Our phylogenetic analysis indicates that the H5N2 LPAI viruses circulating in Mexico and neighboring countries since 1994 have undergone antigenic drift away from vaccine seed strains. Here we evaluated the efficacy of a new recombinant fowlpox virus vector containing an updated H5 insert (rFPV-H5/2016), more relevant to the current strains circulating in Mexico. We tested the vaccine efficacy against a closely related subcluster 4 Mexican H5N2 LPAI (2010 H5/LP) virus and the historic H5N2 HPAI (1995 H5/HP) virus in White Leghorn chickens. The rFPV-H5/2016 vaccine provided hemagglutinin inhibition (HI) titers pre-challenge against viral antigens from both challenge viruses in almost 100% of the immunized birds, with no differences in number of birds seroconverting or HI titers among all tested doses (1.5, 2.0, and 3.1 log10 mean tissue culture infectious doses/bird). The vaccine conferred 100% clinical protection and a significant decrease in oral and cloacal virus shedding from 1995 H5/HP virus challenged birds when compared to the sham controls at all tested doses. Virus shedding titers from vaccinated 2010 H5/LP virus challenged birds significantly decreased compared to sham birds especially at earlier time points. Our results confirm the efficacy of the new rFPV-H5/2016 against antigenic drift of LPAI virus in Mexico and suggest that this vaccine would be a good candidate, likely as a primer in a prime-boost vaccination program.
Assuntos
Varíola Aviária/prevenção & controle , Glicoproteínas de Hemaglutininação de Vírus da Influenza/imunologia , Vírus da Influenza A Subtipo H5N2/imunologia , Vacinas contra Influenza/administração & dosagem , Animais , Galinhas , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Vacinas contra Influenza/genética , México , Filogenia , Vacinas Sintéticas/genéticaRESUMO
Two highly pathogenic avian influenza (HPAI) outbreaks have affected commercial egg production flocks in the American continent in recent years; a H7N3 outbreak in Mexico in 2012 that caused 70% to 85% mortality and a H5N2 outbreak in the United States in 2015 with over 99% mortality. Blood samples were obtained from survivors of each outbreak and from age and genetics matched non-affected controls. A total of 485 individuals (survivors and controls) were genotyped with a 600 k single nucleotide polymorphism (SNP) array to detect genomic regions that influenced the outcome of highly pathogenic influenza infection in the two outbreaks. A total of 420458 high quality, segregating SNPs were identified across all samples. Genetic differences between survivors and controls were analyzed using a logistic model, mixed models and a Bayesian variable selection approach. Several genomic regions potentially associated with resistance to HPAI were identified, after performing multidimensional scaling and adjustment for multiple testing. Analysis conducted within each outbreak identified different genomic regions for resistance to the two virus strains. The strongest signals for the Iowa H5N2 survivor samples were detected on chromosomes 1, 7, 9 and 15. Positional candidate genes were mainly coding for plasma membrane proteins with receptor activity and were also involved in immune response. Three regions with the strongest signal for the Mexico H7N3 samples were located on chromosomes 1 and 5. Neuronal cell surface, signal transduction and immune response proteins coding genes were located in the close proximity of these regions.
Assuntos
Galinhas , Resistência à Doença , Influenza Aviária , Animais , Teorema de Bayes , Galinhas/genética , Surtos de Doenças , Resistência à Doença/genética , Vírus da Influenza A Subtipo H5N2 , Vírus da Influenza A Subtipo H7N3 , Influenza Aviária/genética , México , Estados UnidosRESUMO
Since December 2014, the World Organization for Animal Health (OIE, per the French acronym) has been receiving notifications about detections and outbreaks of highly pathogenic avian influenza (HPAI) in North America due to a new reassortant of H5 viruses.
Desde diciembre de 2014, la Organización Mundial de Sanidad Animal (OIE, por sus siglas en francés) está recibiendo notificaciones sobre la detección en Norteamérica de aves infectadas con virus re-asociados de influenza aviar H5 altamente patogénica (IAAP).