2009—2010年华东地区家禽低致病性禽流感病毒的流行病学调查与分析

为了解华东地区家禽中低致病性禽流感病毒（low pathogenic avian influenza viruses,LPAIVs）的分布规律,从2009年10月到2010年9月在华东地区某活禽市场采集鸡、鸭、鹅等家禽的泄殖腔拭子共1 650份,经鸡胚接种和HA、HI试验鉴定,结果从58份样品中分离到了LPAIVs,总分离率为3.51%。所分离到的6种HA亚型及各HA亚型分离率从高到底依次为：H6、H3、H1、H4、H9、H11。从这些样品中鉴定出7种NA亚型,包括N1、N2、N3、N4、N5、N6、N8,二者之间有11种组合。家鸭样品中LPAIVs的分离率为7.28%,显著高于鸡源样品的分离率1.00%和鹅源样品的分离率1.02%。LPAIVs的季节性分布较为明显,3～6月份和10～12月份的分离率较高,而冬季最冷的1月份和夏季最热的7月份则没有分离到。2种或2种以上不同HA亚型混合感染的样品有6份,全部为水禽源样品,占总阳性样品数的10.34%。这些数据表明活禽市场可以作为AIV的一个重要储存库,而家养水禽可作为AIV的一个重要储存宿主,应该继续加强对活禽市场,尤其是家养水禽中AIV的监测。

Epidemiological survey of low pathogenic avian influenza viruses in poultry in Eastern China

To investigate the epidemiology of low pathogenic avian influenza viruses（LPAIVs） in Eastern China,we surveyed LPAIVs in a live-poultry market（LPM） in Eastern China from October 2009 to September 2010,and 58 from 1 650 cloaca swab samples were positive for LPAIVs in isolation when characterized by hemagglutination（HA） and hemagglutination inhibition（HI） tests.These LPAIVs belonged to six HA subtypes,that is H6,H3,H1,H4,H9 and H11,in the order of isolation rate.In addition,seven NA subtypes including N1,N2,N3,N4,N5,N6 and N8 were identified in these LPAIVs.Altogether 11 HA-NA subtype combinations were identified in our study.The isolation rate from domestic ducks was 7.28%,which was much higher than that from chickens（1.00%） and domestic geese（1.02%）.The isolation rate of LPAIVs was distributed with significant seasonal variations,higher during March-June and October-December and lower in the hottest month in summer and coldest month in winter.Six samples were identified to contain viruses of two different HA subtypes simultaneously,accounting for 10.34% of all the positive samples.All six samples of mixed infection were waterfowl-origin.The result indicates that LPM may serve as a gene pool of avian influenza viruses,and domestic waterfowls may act as a reservior of avian influenza viruses,therefore monitoring of avian influenza viruses in LPM,especially in domestic waterfowls,should be reinforced.