Study on prevalence of avian influenza viruses circulating among poultry reared in farms in northern Vietnam

2009-2011年冬季在河内市各农场共采集了4,526份猪、鸭和鸡样本。其中，流感a特异性M基因检出率分别为52%（342/659）、29%（761/ 2669）和39%(468/ 1198)，检出H6N1和H9N2亚型禽流感病毒。系统发育分析显示，这两种亚型携带的基因与在韩国、中国南部东部或日本北部分离的基因接近，表明在越南北部鸭群中传播的aiv可能是由沿东亚飞行路线迁徙的野鸟引入的。

A total of 4,526 samples were collected from pigs, ducks and chickens, in winter seasons of 2009-2011, in farms in Hanoi. Of those, influenza A-specific M gene was detected in 52% (342/659) and in 29% (761/2,669), and 39% (468/1,198) the samples taken from pigs, ducks, and, chicken in the seasons, from which H6N1 and H9N2 subtypes of Avian influenza viruses were isolated. Phylogenetic analyses revealed that these two subtypes carried genes close to those isolated in South Korea, as well as in east southern China or in northern Japan, indicating that AIVs circulating among ducks in northern Vietnam were possibly introduced by wild birds migrating along with the East Asian flyway.