Quantitative Risk Analysis On Avian Influenza Viruses Circulation In Wild Waterfowls Wintering In Jiangsu Province

Avian influenza is a kind of disease syndrome with acute and high infectious spread by contact or respiratory,caused by the avian influenza virus.Which some showed chronic infection without obvious symptoms,while some showed acute infection and can be caused100%mortality. Since the1970s,data suggest that:wild waterfowls are the "natural reservoir" of avian influenza virus, and all HA and NA subtypes were isolated from wild waterfowls which were of no obvious disease symptoms in general. When the avian flu mixed with human influenza, human will infect human influenza and cause the death. So wild waterflow are paid more attention by human.Under the leadership of World Health Organization(WHO),World Organization for Animal Health(OIE),Food and Agriculture Organization(FAO),a worldwide monitoring system had been established by many countries and regions, so as to monitor AIV timely, dynamicly and efficiently,and protect the normal development of the poultry industry and protect the people’s health in the world from bird flu.The experiment was conducted by epidemiological investigation of avian influenza on10kinds of wintering wild waterfowls in Jiangsu Hongze Lake,Gaoyou Lake,Xuyi Wetland. On this basis, we used the "The Agreement on Application of Sanitary and Phytosanitary Measures"(SPS Agreement) and the "International Animal Health Code" and other important laws documentation made by WHO and OIE as theoretical references.Basing on the basic framework of the animal disease risk analysis in import and export of OIE,as well as our laboratory group data accumulated since2004, we collected some available datas from OIE,WHO and other relevant organizations,and also use@Risk software for quantitative risk analysis,to conduct risk analysis on Avian Influenza Virus circulation in wild waterfowls in Hongze Lake,Gaoyou Lake and Xuyi Wetland,and give the risks management recommendations.The study is summarized as follows:In November2009to February2012, a total of591cloacal swabs were collected from10kinds of wild waterfowls in the Hongze Lake, Gaoyou and the Wetland of Xuyi in Jiangsu Province. These cloacal swabs were treated, and then passaged through9day-old SPF chick embryo. The primers of NP gene were designed according to Lee et al.After hemagglutination test, the strains of hemagglutination activity was detected by RT-PCR. method,and the results show that the35strains were influenza virus.The virus positive rate was5.92%(35/591).The HA, NA gene primers were designed according to the designation of influenza virus universal primers Type A influenza virus by Hoffman et al(2001).1strain N2subtype,2strains N8subtype were identified though Reverse-transplate-PCR amplification of HA and NA gene, with T/A cloned and sequenced by Intrivigen,the sequence were sequence analysis by NCBI. What a conclusion can draw based on past data is that the analysis of homologous and Phylogenetic of NA gene showed that three viruses from different ancestors. It show that the N8isolated subtype A/Green-winged Teal/Gaoyou/5/10and A/rufous-necked stint/Japan/6KS0242/2006, A/Green-winged Teal/Xuyi/7/11and A/green-winged teal/ALB/438/1979in the same evolutionary branch;the separation of N2subtype strains A/Spot-billed Duck/Xuyi/8/09and A/duck/Hebei/0710/2009from China in the same evolutionary branch,which shows that wintering wild waterfowls of Jiangsu Province have spreaded the flu virus acrossed the region in the migration process. Therefore it can be inferred that wintering wild waterfowls of the Jiangsu Province has a very important position in the propagation and evolution of the avian influenza virus.Laboratory reseach data in recent years was analysised comprehensively and based on the basic framework of animal disease risk analysis in the OIE import and export, and taking advantage of the OIE, WHO and other relevant organizations and departments, as well as some open research data, used@Risk software to do the quantitative risk analysis. The analysis showed that the risk of wild waterfowls spreading avian flu viruses in Hongze Lake, Gaoyou Lake, Xuyi wetlands is in a high degree of risk (risk average of2.092,90%of the value in the range of1.989-2.192);and the sensitivity analysis to the exposure factor showed that the biggest risk of transmission was the indicator of the role played by the distribution range of hazards object or ecological benefits (because its contribution data is0.53).The risk can be reduced to within appropriate level of protection with some measures were taked on some condition,so as to play a certain role in forecast of bird flu wetland.