We surveyed live-poultry markets in Korea in 2003 and isolated 9 H9N2, 6 H3N2, and 1 H6N1 influenza viruses. Antigenic and phylogenetic analyses showed that all 9 H9N2 isolates were of A/Chicken/Korea/25232-96006/96-like lineage (which caused disease in chickens in Korea in 1996) but were different from H9N2 viruses of southeastern China. They had at least 4 genotypes and replicated in chickens...

Reverse transcriptase PCR designed to amplify the N1 to N9 neuraminidase (NA) genes of avian influenza viruses detected 118 of the 119 NA genes tested (99.2%) in a subtype-specific manner. This technique successfully subtyped all 167 recent avian influenza viruses isolated from birds. Subtype specificity was confirmed by sequence analyses of all 285 PCR products.

Avian H9N2 influenza A virus has caused repeated human infections in Asia since 1998. Here we report that an H9N2 influenza virus infected a 5-year-old child in Hong Kong in 2003. To identify the possible source of the infection, the human isolate and other H9N2 influenza viruses isolated from Hong Kong poultry markets from January to October 2003 were genetically and antigenically characterize...

Highly pathogenic H5N1 avian influenza is considered an avian disease, although there is some evidence of limited human-to-human transmission of the virus. A global effort is underway to control or eradicate the highly pathogenic H5N1 avian influenza virus in poultry and prevent human exposure, both of which may also reduce the risk of pandemic emergence. Hemagglutinin gene sequences from 215 h...

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...

Pandemic influenza virus has its origins in avian influenza viruses. The highly pathogenic avian influenza virus subtype H5N1 is already panzootic in poultry, with attendant economic consequences. It continues to cross species barriers to infect humans and other mammals, often with fatal outcomes. Therefore, H5N1 virus has rightly received attention as a potential pandemic threat. However, it i...

The segmented structure of the influenza virus genome plays a pivotal role in its adaptation to new hosts and the emergence of pandemics. Despite concerns about the pandemic threat posed by highly pathogenic avian influenza H5N1 viruses, little is known about the biological properties of H5N1 viruses that may emerge following reassortment with contemporary human influenza viruses. In this study...

We report the serological evidence of low-pathogenic avian influenza (LPAI) H9N2 infection in an occupational poultry-exposed population and a general population. A serological survey of an occupational poultry-exposed population and a general population was conducted using a haemagglutinin-inhibiting (HI) assay in Shanghai, China, from January 2008 to December 2010. Evidence of higher anti-H9 ...

Potential conflicts of interest: F.H. has received payment as a consultant and grant support from several pharmaceutical companies involved in the development of antiviral drugs and vaccines for influenza. The views expressed in this article are those of Dr. Croisi-er and do not necessarily reflect those of the World Health Organization. Reports of seropositivity for different avian influenza A...