Ecoepidemiology of tularemia in the Southcentral United States

Division of Vector-Borne Infectious Diseases, National Center for Zoonotic, Vector-Borne, and Enteric Diseases, Centers for Disease Control and Prevention, Fort Collins, Colorado 80522, USA.
The American journal of tropical medicine and hygiene (Impact Factor: 2.7). 05/2008; 78(4):586-94.
Source: PubMed


We combined county-based data for tularemia incidence from 1990 to 2003 for a nine-state region (Arkansas, Illinois, Indiana, Kansas, Kentucky, Missouri, Nebraska, Oklahoma, and Tennessee) in the southcentral United States with Geographic Information System (GIS)-based environmental data to determine associations between coverage by different habitats (especially dry forest representing suitable tick habitat) and tularemia incidence. High-risk counties (> 1 case per 100,000 person-years) clustered in Arkansas-Missouri and far eastern Oklahoma and Kansas. County tularemia incidence was positively associated with coverage by dry forested habitat suitable for vector ticks for Oklahoma-Kansas-Nebraska and Arkansas-Missouri but not for Illinois-Indiana-Kentucky-Tennessee. A multivariate logistic regression model predicting presence of areas with risk of tularemia based on GIS-derived environmental data was developed for the Arkansas-Missouri tularemia focus. The study shows the potential for research on tularemia ecoepidemiology and highlights the need for further modeling efforts based on acarologic data and more fine-scale point or zip code/census tract epidemiologic data.

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    • "For example, abundance of the tick genus Ixodes, one of which is the vector primarily responsible for the transmission of Lyme disease (LD), is associated with temperature, landscape slope [3], forested areas with sandy soils [4], and increasing residential development [5]. Tularemia prevalence is positively associated with dry forested habitat areas [6]. Human populations living within forested areas and on specific soils are at higher risk of contracting LD [7] [8]. "
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