Background: Avian influenza A has been a major threat to worldwide public health. The evolutionary patterns of the pathogenic viruses between humans and birds are essential to effective monitoring of disease propagation. In this study, we focused on finding an appropriate evolutionary measure for avian influenza A to reflect its adaptation to human hosts and outbreaks in human population. We es...

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...

Since the mid-1970s, Hong Kong has functioned as an influenza sentinel post for southern China, a region identified as a hypothetical epicentre for the emergence of pandemic influenza viruses. Nineteen ninety-seven marked the coming-of-age of animal-influenza studies with the recognition in Hong Kong of an incipient pandemic situation brought about by the infection of chicken and humans with an...

In 1997, 18 cases of influenza in Hong Kong (bird flu) caused by a novel H5N1 (chicken) virus resulted in the deaths of six individuals and once again raised the specter of a potentially devastating influenza pandemic. Slaughter of the poultry in the live bird markets removed the source of infection and no further human cases of H5N1 infection have occurred. In March 1999, however, a new pandem...

Background and Aims: Influenza A virus subtype H9N2 have continued to circulate in domestic poultry farms in Asia since 1998. The virus circulates in live bird markets, missing link in epidemiology of avian influenza. Regarding previous studies on H9N2 viruses of Iran and having no data on this subject in Iranian live bird markets this study was conducted to analyze genetically hemagglutinin pr...

From 2014 to 2015, three cases of highly pathogenic avian influenza infection occurred in zoo-housed north-east China tigers (Panthera tigris ssp.altaica) and four tigers died of respiratory distress in succession in Yunnan Province, China. We isolated and characterized three highly pathogenic avian influenza A(H5N1) viruses from these tigers. Phylogenetic analysis indicated that A/tiger /Yunna...

Aim The objective of the present study was to prepare a trivalent inactivated vaccine of Newcastle disease virus (NDV), H5N1, and H9N2 viruses. Materials and Methods Three monovalent and a trivalent vaccines were prepared by emulsifying inactivated NDV (LaSota strain), reassortant H5N1, and H9N2 viruses with Montanide ISA 71 oil adjuvant. Parameters used for evaluation of the efficacy of the ...

Avian influenza viruses (AIV) of H5N1 and H9N2 subtypes have zoonotic and pandemic potential. 377 out of 633 human infections with H5N1 virus were fatal and human infections by H9N2 virus were infrequently reported to the World Health Organization. Some H9N2 viruses either possessed genes similar to the H5N1 virus or were claimed to donate gene segments to H5N1 virus. Both features were reporte...

Influenza H9N2 subtype viruses and their reassortants (such as H7N9) are posing increasing threats to birds and humans in China. During 2009-2013, multiple novel subtype viruses with H9N2 original genes emerged in China. Yet, the genetic evolution of H9N2 viruses in various host organisms in China has not been systematically investigated since 2009. In the present study, we performed large-scal...

The H9N2 avian influenza virus circulates worldwide, predominantly in poultry. Its increasing infectivity and adaptation in poultry and mammals have enhanced the possibility of human infection. However, H9N2 human cases are difficult to detect due to their mild clinical symptoms. Serological study is valuable for risk assessment. A total of 15,700 serum samples were collected from occupationall...