Secure Food Systems Team, Department of Veterinary and Biomedical Sciences, University of Minnesota, Saint Paul, Minnesota, United States of America.
Department of Bacteriology and Epidemiology, Wageningen Bioveterinary Research, Wageningen University and Research Centre, Lelystad, The Netherlands.
PLoS One. 2018 Sep 21;13(9):e0204262. doi: 10.1371/journal.pone.0204262. eCollection 2018.
The spatial spread of highly pathogenic avian influenza (HPAI) H5N2 during the 2015 outbreak in the U.S. state of Minnesota was analyzed through the estimation of a spatial transmission kernel, which quantifies the infection hazard an infectious premises poses to an uninfected premises some given distance away. Parameters were estimated using a maximum likelihood method for the entire outbreak as well as for two phases defined by the daily number of newly detected HPAI-positive premises. The results indicate both a strong dependence of the likelihood of transmission on distance and a significant distance-independent component of outbreak spread for the overall outbreak. The results further suggest that HPAI spread differed during the later phase of the outbreak. The estimated spatial transmission kernel was used to compare the Minnesota outbreak with previous HPAI outbreaks in the Netherlands and Italy to contextualize the Minnesota transmission kernel results and make additional inferences about HPAI transmission during the Minnesota outbreak. Lastly, the spatial transmission kernel was used to identify high risk areas for HPAI spread in Minnesota. Risk maps were also used to evaluate the potential impact of an early marketing strategy implemented by poultry producers in a county in Minnesota during the outbreak, with results providing evidence that the strategy was successful in reducing the potential for HPAI spread.
2015 年美国明尼苏达州高致病性禽流感（HPAI）H5N2 的空间传播通过估计空间传播核来分析，该核量化了感染风险，即一个感染场所对一定距离外的未感染场所造成的感染危险。使用最大似然法对整个疫情以及由新发现的 HPAI 阳性场所数量确定的两个阶段分别估计参数。结果表明，传播的可能性强烈依赖于距离，而且疫情传播存在显著的与距离无关的成分。结果进一步表明，HPAI 在疫情后期的传播有所不同。所估计的空间传播核用于将明尼苏达州的疫情与荷兰和意大利之前的 HPAI 疫情进行比较，以了解明尼苏达州的传播核结果，并对明尼苏达州疫情期间的 HPAI 传播做出更多推断。最后，空间传播核用于确定明尼苏达州 HPAI 传播的高风险区域。风险图还用于评估疫情期间明尼苏达州一个县的家禽养殖户实施的早期营销策略的潜在影响，结果表明该策略成功降低了 HPAI 传播的可能性。
