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...

conclusions after seven consecutive passages of both cell cultures, the h9n2 virus showed similar antigenicity, also no change on viral titer level and virus replication behavior in adaptation was found. the results highlighted the use of a549 cells for efficient virus isolation. results the influenza virus infectivity was not significant difference in these cells in the presence of trypsin. th...

BACKGROUND: The H9N2 subtype of avian influenzaviruses (AIVs) has been isolated in multiple avian species inmany European, Asian, African and American countries. Sincethe first outbreak of H9N2 virus in Iran in 1998, this virus haswidely circulated throughout the country, resulting in majoreconomic losses in chicken flocks. Several amino acids in thevirus ribonucleoprotein (RNP) complex includi...

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...

BACKGROUND Swine are important hosts for influenza A viruses playing a crucial role in the epidemiology and interspecies transmission of these viruses. Respiratory epithelial cells are the primary target cells for influenza viruses. METHODOLOGY/PRINCIPAL FINDINGS To analyze the infection of porcine airway epithelial cells by influenza viruses, we established precision-cut lung slices as a cul...

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...

The objective of this study was to compare the effect of two conventional H9N2 avian influenza (AI) vaccines on replication and shedding of the H9N2 AI virus in broiler chickens. These inactivated oil emulsion vaccines contain either a UAE or an Iranian H9N2 AI isolate. One hundred and fifty one-day-old commercial broiler chickens were randomly divided into six groups. The birds, except for the...

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...

H9N2 influenza A viruses are currently widespread in chickens, quail, and other poultry in Asia and have caused a few cases of influenza in humans. In this study, we found that H9N2 viruses from Hong Kong live bird markets have receptor specificity similar to that of human H3N2 viruses. In addition, the neuraminidase of poultry H9N2 viruses has mutations in its hemadsorbing site, a characterist...

Tree sparrows (Passer montanus) are widely distributed in all seasons in many countries. In this study, a survey and relevant experiments on avian influenza (AI) in tree sparrows were conducted. The results suggested that the receptor for avian influenza viruses (AIVs), SAα2,3Gal, is abundant in the respiratory tract of tree sparrows, and most of the tree sparrows infected experimentally with t...