Influenza A viruses of subtype H9N2 are wide spread among poultry and other mammalian species. Crossing the species barrier from poultry to human occurred in recent years creating a pandemic of H9N2 virus. It is known that the pathogenicity of H9N2 is lower than H5N1. Nonetheless, it is important to establish the molecular functions of H9N2 viral proteins. We studied mutations in the polymerase...

INTRODUCTION Avian influenza viruses of the H9N2 subtype have been reported to cause human infections. This study demonstrates the impact of nasal viral passaging of avian H9N2 in hamsters on its cross species-pathogenic adaptability and variability of amino acid sequences of the hemagglutinin (HA) and neuraminidase (NA) stalk. METHODOLOGY Three intranasal passagings of avian H9N2 in hamsters...

To prevent H9N2 avian influenza virus infection in chickens, a long-term vaccination program using inactivated vaccines has been implemented in China. However, the protective efficacy of inactivated vaccines against antigenic drift variants is limited, and H9N2 influenza virus continues to circulate in vaccinated chicken flocks in China. Therefore, developing a cross-reactive vaccine to control...

Avian influenza (AI) H9N2 has been reported from poultry in India. A seroepidemiological study was undertaken among poultry workers to understand the prevalence of antibodies against AI H9N2 in Pune, Maharashtra, India. A total of 338 poultry workers were sampled. Serum samples were tested for presence of antibodies against AI H9N2 virus by hemagglutination inhibition (HI) and microneutralizati...

Both H9N2 avian influenza and 2009 pandemic H1N1 viruses (pH1N1) are able to infect humans and swine, which has raised concerns that novel reassortant H9 viruses with pH1N1 genes might be generated in these hosts by reassortment. Although previous studies have demonstrated that reassortant H9 viruses with pH1N1 genes show increased virulence in mice and transmissibility in ferrets, the virulenc...

H9N2 avian influenza viruses are endemic in poultry in Asia and the Middle East. These viruses sporadically cause dead-end infections in pigs and humans raising concerns about their potential to adapt to mammals or reassort with human or swine influenza viruses. We performed ten serial passages with an avian H9N2 virus (A/quail/Hong Kong/G1/1997) in influenza naïve pigs to assess the potential ...

H9N2 influenza viruses circulate in wild birds and poultry in Eurasian countries, and have been isolated from pigs and humans in China. H9N2 viruses isolated from birds, pigs and humans have been classified into three sublineages based on antigenic and genetic features. Chicken antisera to H9N2 viruses of the Korean sublineage reacted with viruses of different sublineages by the hemagglutinatio...