中国猪源H5N1和H9N2亚型流感病毒的分离鉴定

Isolation and characterization of H5N1 and H9N2 influenza viruses from pigs in China

猪是禽流感病毒"禽＿猪＿人"传播链中重要的中间宿主,了解猪流感的疫情动态将为动物流感及人流感的疾病预测及防制提供重要依据。1999～2001年间进行的血清学和病毒学监测发现我国猪群存在大范围的H1和H3亚型猪流感感染(李海燕等,2002)。2002～2003年,我们进一步对来自全国14个省市的1936份血清进行了H9亚型猪流感的检测,同时在广东、福建等省进行了H5亚型猪流感的检测。2002年辽宁、广东、山东及重庆猪血清中出现H9亚型流感抗体,阳性率分别为7.3%、6.8%、5.1%和1.6%。2003年采集的猪血清H9亚型流感抗体均为阴性,同时发现广东、福建两省2003年出现H5亚型流感阳性猪群,阳性率分别为4.7%和8.2%。从2001～2003年收集和送检的样品中分离鉴定了6株H9N2亚型和2株H5N1亚型猪流感病毒,部分序列分析发现H9和H5亚型猪流感病毒均与我国分离的禽流感病毒高度同源。本研究进一步确证了我国猪群中存在H9N2亚型流感病毒,并且首次发现我国猪群已出现H5N1亚型流感病毒,为人类流感及动物流感的防制敲响了警钟。对这两个亚型流感病毒所具有的公共卫生和兽医公共卫生危害性应予以高度重视。

Pigs can be served as a very important intermediate host for the interspecies transmission of avian influenza virus; therefore, the surveillance of swine influenza will provide important information for the prediction and pandemic preparedness of animal and human influenza. Serological and virologic studies conducted from 1999～2001 indicated that H1 and H3 subtype influenza infections have been widely existed in the pig flocks in China (Haiyan Li, et al, 2002). During 2002～2003, 1936 sera samples were collected from the pig flocks of 14 provinces and cities for H9 subtype influenza detection. 7.3 %、6.8 %、4.5 %and 1.9 % seropositivity rates against avian H9 subtype virus were detected in serum samples collected in 2002 from Liaoning, Guangdong, Shandong provinces and Chongqing city, respectively. H9 subtype was not detected from serum samples collected in 2003, however, 4.7 % and 8.2 % of H5 subtype influenza positive were detected from serum samples which collected from Guangdong and Fujian provinces. Six H9N2 and 2 H5N1 subtype influenza viruses were isolated from the samples that were collected during 2001～2003. Sequence analysis confirmed that these viruses are highly related with the H9N2 or H5N1 subtype avian influenza viruses that have been isolated in China. This study confirms the H9N2 influenza infection in the pig flocks in China, and also is the first report of the emergency of the H5N1 influenza virus in the pig species. Therefore, for both the veterinary and public health, urgent attention should be paid to the pandemic preparedness of these two subtypes influenza.