Transmissibility of Influenza A Viruses

描述（由申请人提供）：本提案的长期目标是产生可用于准备或预防大流行性流感的知识。流感病毒的种间传播是大流行性流感毒株产生的关键因素。虽然对产生潜在的人类大流行毒株所需的分子步骤知之甚少，但中间宿主被认为是必要的。水禽是甲型流感病毒的天然宿主，但香港从人类身上分离出的甲型流感病毒（1997年的H5N1和1999年的H9N2）含有在陆基鸟类，特别是中国南方广泛养殖的鹌鹑中传播和适应的基因。流行病学证据和我们的初步结果强烈表明，鹌鹑可能在陆地鸟类中发挥独特的作用，在新型甲型流感病毒的出现中可以跨越物种屏障。

DESCRIPTION (provided by applicant): The long-term objective of this proposal is to generate knowledge that may be used to prepare for or prevent pandemic influenza. The interspecies transmission of influenza viruses is a key element in the generation of a pandemic influenza strain. Although little is known about the molecular steps required to create a potential human pandemic strain, intermediate hosts are considered necessary. Aquatic birds are the natural reservoir of influenza A viruses, but the influenza A viruses isolated from humans in Hong Kong (H5N1 in 1997 and H9N2 in1999) contained genes that had circulated and adapted in land-based birds, particularly quail, which are widely farmed in Southern China. Epidemiological evidence and our preliminary results strongly suggest that quail could play a unique role among land-based birds in the emergence of novel influenza A viruses that can cross the species barrier. The proposed research will use molecular, classical virologic, and reverse genetics methods to define 1) the role of land-based birds, particularly quail, as intermediate hosts in interspecies transmission and spread of influenza A viruses; and 2) the molecular basis of the transmissibility of influenza A viruses in land-based avian intermediate hosts. With poultry production increasing worldwide (more than 200% since the 1960's), the mechanisms underlying interspecies transmission of influenza viruses must be elucidated if the emergence of a pandemic influenza strain is to be forestalled or adequately prepared for. The techniques needed to obtain this information are now available, and the results will lay the groundwork for important changes in agricultural policies and pandemic planning.