| Summary: | 碩士 === 國立中興大學 === 微生物暨公共衛生學研究所 === 106 === Since 2014, new subtypes of high pathogenic avian influenza virus (HPAIV) descendant from H5 clade 2.3.4.4 viruses have emerged from China and spread to worldwide rapidly through the migrating bird flyway. To date, no human case had been reported, but the new clade of HPAIV has caused among poultry farms, even result in huge socio-economic impacts due to the losses of birds killed by the disease or by culling, and from the disruption of trade and market activities imposed by disease control measures such as movement restrictions and a temporary ban of poultry product exports. From 2015 to 2017 in Taiwan, there were 1004 poultry farms, 37 poultry farms and 182 poultry farms confirmed as HPAIV positive were reported. The subtypes caused the HPAIV epidemic in 2015 were H5N2, H5N3 and H5N8. In 2016, the subtypes of HPAIV were H5N2 and H5N8. And in 2017, the subtypes of HPAIV were H5N2, H5N6 and H5N8. HPAIV causes the serious symptom in poultry, and will be the great threaten in public health if it is possible that HPAIV transmit to human from poultry or human. The objectives of this study is to identify the spatial clusters, hot spot, with Global Moran''s I and Local Moran''s I analysis methods and find out the associated environmental factors resulting in the clustering with the stepwise multivariate logistic regression analysis. According to the distribution of the HPAIV case-points, most points were in the western of Yunlin County and in the north of Pingtung County. The result of Global Moran''s I indicated that the distribution of the HPAIV cases in Taiwan had the spatial autocorrelation in the radius of 3km distance. Through the Local Moran''s I, spatial analysis, the hot spots of the HPAIV outbreaks in 2015 to 2017 in Taiwan were in the western of Yunlin County and in the north of Pingtung County. Next, we examined 17 different variables between the hot spots and non-hot spots by the stepwise multivariate logistic regression analysis. Based on the result of the stepwise multivariate logistic regression analysis, the four risk factors strongly associated with the HPAIV hot spots throughout three consecutive years were the farm density of non-register waterfowl farms, the index of waterfowl-chicken mixed farming per unit area, highly degree of farm density and the coverage of the cropping farms. That meant the outbreaks of HPAIV in Taiwan were related to the concentration of poultry farms were too over, the active area of waterfowl and non-waterfowl were to closed and the exist of resident birds. Final we used the results of the stepwise multivariate logistic regression analysis, we developed the risk map and predict the high risk area of the HPAIV outbreak in Taiwan in the future. This study points out the environmental factors and developed the risk map, which will assist in future surveillance and disease control among the poultry farms for avian influenza epidemic in Taiwan.
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