The recent human infections caused by H5N1, H9N2, and H7N7 avian influenza viruses highlighted the continuous threat of new pathogenic influenza viruses emerging from a natural reservoir in birds. It is generally believed that replication of avian influenza viruses in humans is restricted by a poor fit of these viruses to cellular receptors and extracellular inhibitors in the human respiratory ...

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...

Zoonotic transmission of pathogenic avian influenza virus (AIV) is a potential public health threat (1, 2), as the virus may acquire human-to-human transmissibility through mutations or by reassortment with seasonal influenza viruses (e.g., H3N2 and H1N1). The recent outbreak of novel H7N9 virus in China is an enigma (3). In contrast to outbreaks of human infections by other avian influenza vir...

A(H5N1) virus, for which only 2 of the serum specimens we tested were positive (data not shown), but much lower than the seropositivity level for low pathogenicity avian influenza A(H9N2) virus; 3.4% of the samples tested were positive for A/Chicken/Hong Kong/ G9/1997(H9N2)–like virus (data not shown). A previous US study has reported H6N2-positive antibodies in veterinarians (9). Our results a...

In April 1999, isolation of avian influenza A (H9N2) viruses from humans was confirmed for the first time. H9N2 viruses were isolated from nasopharyngeal aspirate specimens collected from two children who were hospitalized with uncomplicated, febrile, upper respiratory tract illnesses in Hong Kong during March 1999. Novel influenza viruses have the potential to initiate global pandemics if they...

In recent years, high pathogenicity avian influenza (HPAI) virus, H5N1, low pathogenicity avian influenza (LPAI) virus, H9N2, and both HPAI and LPAI H7 viruses have proved devastating for the affected economies reliant on poultry industry, and have posed serious public health concerns. These viruses have repeatedly caused zoonotic disease in humans, raising concerns of a potential influenza pan...

BACKGROUND Limited knowledge about the molecular mechanism of avian influenza H9N2 virus pathogenicity in birds as well as human hosts has limited the development of effective control against the disease. To overcome this issue detailed understanding of the infectious characteristics of the virus in host cells should be obtained. OBJECTIVES In this study we examined the replication kinetics o...

Among the avian influenza A virus subtypes, the H5N1 and H9N2 viruses have the potential to cause an influenza pandemic because they are widely prevalent in avian species in Asia and have demonstrated the ability to infect humans (8). Currently, human infections with wild-type (wt) strains of these viruses could occur in the United States in poultry and turkey farm workers and in travelers retu...

Avian influenza virus (AIV) can infect birds and mammals, including humans, and are thus a serious threat to public health. Vaccination is vital for controlling AIV circulation. In this study, we generated a recombinant lactobacillus expressing the NP-M1-DCpep of H9N2 avian influenza virus and evaluated the activation effect of NC8-pSIP409-NP-M1-DCpep on dendritic cells (DCs) in a mouse model. ...

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...