Avian influenza virus subtype H9N2 (H9N2) and Chlamydia psittaci (C. psittaci) are frequently isolated in chickens with respiratory disease. However, their roles in co-infection remain unclear. We tested the hypothesis that C. psittaci enhances H9N2 infection through suppression of host immunity. Thus, 10-day-old SPF chickens were inoculated intra-tracheally with a high or low virulence C. psit...

The complete genomic sequence of a new H9N2 avian influenza virus (AIV), isolated in northwestern China, was determined. Sequence and phylogenetic analyses based on the sequences of eight genomic segments revealed that the isolate is phylogenetically related to the Y280-like sublineage.

Abstract : Avian influenza virus (AIV) infection is a major cause of influenza mortality in birds and can cause human mortality and morbidity. Although the risk of infection with avian influenza virus (AIV) is generally low for most people, the pathogenic virus can cross the species barrier and acquires the ability to infect and be transmitted among the human population; therefore the ra...

The PB1-F2 protein of influenza A virus has been considered a virulence factor, but its function in inducing apoptosis may be of disadvantage to viral replication. Host mechanisms to regulate PB1-F2-induced apoptosis remain unknown. We generated a PB1-F2-deficient avian influenza virus (AIV) H9N2 and found that the mutant virus replicated less efficiently in human lung epithelial cells. The PB1...

Previous studies indicate that the H3 influenza virus has the ability to establish infection upon interspecies transmission and poses a threat to mammals. Therefore, it is important to enhance the surveillance of H3 avian influenza viruses (AIVs). In this study, A/duck/Shanghai/C84/2009(H3N2) (C84) was isolated from a live poultry market in Shanghai, China. Using PCR and sequencing analyses, we...

Pandemic influenza is a zoonosis. Studies on influenza ecology conducted in Hong Kong since the 1970s in which Hong Kong essentially functioned as an influenza sentinel post indicated that it might be possible, for the first time, to have influenza preparedness at the baseline avian level. This appreciation of influenza ecology facilitated recognition of the H5N1 'bird flu' incident in Hong Kon...

Despite their classification as low pathogenicity avian influenza viruses (LPAIV), A/H9N2 viruses cause significant losses in poultry in many countries throughout Asia, the Middle East and North Africa. To date, poultry surveillance in Vietnam has focused on detection of influenza H5 viruses, and there is limited understanding of influenza H9 epidemiology and transmission dynamics. We determine...

BACKGROUND H9N2 avian influenza viruses continue to spread in poultry and wild birds throughout Eurasia. OBJECTIVES To characterize H9N2 influenza viruses from pheasants, quail, and white-bellied bustards (WBBs) used to train falcons in the United Arab Emirates (UAE). METHODS Four H9N2 viruses were isolated from pheasants, quail, and WBB used for falconry in the UAE, and antigenic, molecula...

Influenza virus surveillance, poultry outbreak investigations and genomic sequencing were assessed to understand the ecology and evolution of low pathogenicity avian influenza (LPAI) A viruses in Bangladesh from 2007 to 2013. We analyzed 506 avian specimens collected from poultry in live bird markets and backyard flocks to identify influenza A viruses. Virus isolation-positive specimens (n = 50...

BACKGROUND A(H5N1) and A(H9N2) avian influenza viruses are enzootic in Egyptian poultry, and most A(H5N1) human cases since 2009 have occurred in Egypt. Our understanding of the epidemiology of avian viruses in humans remains limited. Questions about the frequency of infection, the proportion of infections that are mild or subclinical, and the case-fatality rate remain largely unanswered. MET...