ETIDIOH - NEW

ABSTRACT As companion animals, dogs are susceptible to various subtypes of influenza A virus (IAV), with the H3N2 and H3N8 subtypes of canine influenza virus (CIV) stably circulating among canines . Compared to the H3N8 CIV, the H3N2 CIV is more widely prevalent in canine populations and demonstrates increased adaptability to mammals , potentially facilitating cross-species transmission . Therefore, a comprehensive elucidation of the mechanisms underlying H3N2 CIV adaptation to mammals is imperative. In this study, we serially passaged the GD14-WT strain in murine lungs , successfully establishing a lethal H3N2 CIV infection model . From this model, we isolated the lethal strain GD14-MA and identified the key lethal mutations PA(S184N) and PB2(E627K). Moreover, the GD14-ma[PA(S184N)+PB2(E627K)] strain exhibited markedly enhanced pathogenicity in dogs . Viral titers in lung tissues from infected dogs and mice showed that GD14-ma[PA(S184N)+PB2(E627K)] does not increase its pathogenicity ...

Highlights •  This is the first report of clade 2.3.4.4b H5N1 virus from India. •  Evidence of novel reassortment between H5N1 and low pathogenic H3N8 viruses. •  Absence of H5N1 infection among people with probable exposure. Abstract H5N1 viruses belonging to clade 2.3.4.4b have caused unprecedented outbreaks globally. Outbreaks of H5N1 virus were reported in poultry and wild birds from Kerala (India) in the year 2024. Samples from birds and the environment were collected . Real-time RT-PCR and virus isolation using embryonated chicken eggs were carried out. Eight out of 20 samples were positive for virus isolation. The virus showed avian type receptor specificity using sialidase assay. Full genome sequencing revealed markers associated with high pathogenicity and mammalian adaptation . All the viruses belonged to a single genotype with multiple reassortments , including internal gene segments from an avian influenza (AI) H3N8 virus reported from Kerala . Surveillance am...

ABSTRACT Recent avian-origin H3N8 influenza A virus (IAV) that have infected humans pose a potential public health concern . Alterations in the viral surface glycoprotein, hemagglutinin (HA), are typically required for IAVs to cross the species barrier for adaptation to a new host, but whether H3N8 has adapted to infect humans remains elusive. The observation of a degenerative codon in position 228 of HA in human H3N8 A/Henan/4-10/2022 protein sequence , which could be residue G or S, suggests a dynamic viral adaptation for human infection. Previously, we found this human-isolated virus has shown the ability to transmit between ferrets via respiratory droplets , with the HA-G228S substitution mutation emerging as a critical determinant for the airborne transmission of the virus in ferrets. Here, we investigated the receptor-binding properties of these two H3N8 HAs. Our results showed H3N8 HAs have dual receptor-binding properties with a preference for avian receptor binding , and G228S...

Abstract Equine influenza (EI) is a highly contagious respiratory disease caused by the equine influenza virus (EIV), posing a significant threat to equine populations worldwide . EIV exhibits considerable antigenic variability due to its segmented genome, complicating long-term disease control efforts. Although infections are rarely fatal , EIV’s high transmissibility results in widespread outbreaks, leading to substantial morbidity and considerable economic impacts on veterinary care, quarantine, and equestrian activities. The H3N8 subtype has undergone significant antigenic evolution , resulting in the emergence of distinct lineages , including Eurasian and American , with the Florida sublineage being particularly prevalent. Continuous genetic surveillance and regular updates to vaccine formulations are necessary to address antigenic drift and maintain vaccination efficacy. Additionally, rare cross-species transmissions have raised concerns regarding the zoonotic potential of EIV. T...

Abstract Since 2022, three cases of human infections of novel H3N8 avian influenza viruses (AIVs) have been confirmed in China . Given the potential for significant public health implications , the prompt detection and containment of the virus is particularly important. Comprehensive analyses were conducted of the complete viral gene sequences of five H3 subtype AIVs that were isolated from chickens, pigeons, and geese in live poultry markets in China in 2023. Four strains exhibited a high degree of homology with the H3N8 viruses responsible for human infections in 2022 and 2023. A subsequent study was conducted to investigate the pathogenicity differences among multiple subtypes of the H3 AIVs in chickens. The study revealed that all infected chickens exhibited clinical signs and viral shedding. Notably, two H3N8 viruses, which were highly homologous to human strains, demonstrated significant differences in adaptability to chickens. The goose-derived H3N5 strain displayed high adaptab...

Abstract Crocodilians are susceptible to a range of virus infection including influenza A virus (IAV). However, little is known about the ecology and epidemiology of IAV in crocodile species. This study aimed to investigate IAV infection in farmed Siamese crocodiles in central Thailand . We collected plasma samples and pharyngeal swab samples from Siamese crocodiles residing in 13 crocodile farms in 9 provinces of central Thailand during 2019. Additional archival plasma samples of Siamese crocodiles collected in 2012 and 2018 were also included in the study. Plasma samples were screened for influenza A antibodies by a hemagglutination inhibition (HI) assay and positive were evaluated by a cytopathic effect/hemagglutination based- microneutralization (MN) assay . Swab samples were tested for influenza viral RNA by a real-time RT-PCR assay targeting the influenza matrix (M) gene. Among 246 tested plasma samples, the overall seroprevalence of antibodies against IAV in farmed Siamese croco...

Abstract Recent outbreaks of influenza A(H5N1) have affected many mammal species . We report serologic evidence of H5N1 virus infection in horses in Mongolia . Because H3N8 equine influenza virus is endemic in many countries, horses should be monitored to prevent reassortment between equine and avian influenza viruses with unknown consequences. Source: Emerging Infectious Diseases Journal,  https://wwwnc.cdc.gov/eid/article/31/1/24-1266_article _____

Abstract Infectious bursal disease virus (IBDV) is endemic worldwide and causes immunosuppression in chickens . We hypothesized that a previous history of IBDV in chickens would render them more susceptible to infection by influenza A viruses (IAVs) from aquatic waterfowl reservoirs . To model this, we inoculated 14 day old specific pathogen free (SPF) chickens with a low pathogenicity avian influenza (LPAI) virus strain from a mallard ( A/Mallard/Alberta/156/01 (H3N8) ) and compared replication and shedding between immunocompetent chickens and chickens that had immune dysregulation due to a prior IBDV infection with strain F52/70 (genogroup A1B1) at 2 days of age. The mallard IAV strain replicated in the upper respiratory tract of the chickens , and virus was shed from the oropharyngeal cavity , but there was no shedding from the cloaca , and no transmission to sentinel chickens . Replication of the mallard IAV in the chicken host was associated with amino acid substitutions in the po...