Poxvirus and Rabies Branch, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
Vector Borne Zoonotic Dis. 2012 Feb;12(2):126-37. doi: 10.1089/vbz.2010.0053. Epub 2011 Oct 13.
Although raccoons are widely distributed throughout North America, the raccoon rabies virus variant is enzootic only in the eastern United States, based on current surveillance data. This variant of rabies virus is now responsible for >60% of all cases of animal rabies reported in the United States each year. Ongoing national efforts via an oral rabies vaccination (ORV) program are aimed at preventing the spread of raccoon rabies. However, from an epidemiologic perspective, the relative susceptibility of naïve geographic localities, adjacent to defined enzootic areas, to support an outbreak, is unknown. In the current study, we tested the ability of a spatial risk model to forecast raccoon rabies spread in presumably rabies-free and enzootic areas. Demographic, environmental, and geographical features of three adjacent states (Ohio, West Virginia, and Pennsylvania), which include distinct raccoon rabies free, as well as enzootic areas, were modeled by using a Poisson Regression Model, which had been developed from previous studies of enzootic raccoon rabies in New York State. We estimated susceptibility to raccoon rabies emergence at the census tract level and compared the results with historical surveillance data. Approximately 70% of the disease-free region had moderate to very high susceptibility, compared with 23% in the enzootic region. Areas of high susceptibility for raccoon rabies lie west of current ORV intervention areas, especially in southern Ohio and western West Virginia. Predicted high susceptibility areas matched historical surveillance data. We discuss model implications to the spatial dynamics and spread of raccoon rabies, and its application for designing more efficient disease control interventions.
尽管浣熊广泛分布于北美洲，但根据目前的监测数据，浣熊狂犬病病毒变异株仅在美东地区流行。这种变异株的狂犬病病毒现在导致了美国每年报告的动物狂犬病病例的 60%以上。目前正在通过口服狂犬病疫苗（ORV）计划进行全国性的努力，旨在预防浣熊狂犬病的传播。然而，从流行病学的角度来看，未知邻近明确流行地区的、相对易感的地理区域是否会支持暴发。在当前的研究中，我们测试了空间风险模型预测假定无狂犬病和流行地区浣熊狂犬病传播的能力。使用泊松回归模型对三个相邻州（俄亥俄州、西弗吉尼亚州和宾夕法尼亚州）的人口统计学、环境和地理特征进行建模，该模型是根据纽约州流行的浣熊狂犬病的先前研究开发的。我们在普查区层面估计了浣熊狂犬病出现的易感性，并将结果与历史监测数据进行了比较。与流行地区的 23%相比，无病地区约有 70%的地区具有中度到高度的易感性。浣熊狂犬病的高易感性区域位于当前 ORV 干预区域的西部，尤其是在俄亥俄州南部和西弗吉尼亚州西部。预测的高易感性区域与历史监测数据相匹配。我们讨论了模型对浣熊狂犬病空间动态和传播的影响，以及其在设计更有效的疾病控制干预措施方面的应用。
