Seroepidemiology of Coxiella burnetii in Wild White-Tailed Deer (Odocoileus virginianus) in New York, United States

Coxiella burnetii is an environmentally resistant bacterium that has been reported in wildlife populations. Frequent contact on pasture between white-tailed deer (Odocoileus virginianus) and cattle has been reported by farmers in the Northeast U.S., and transmission of C. burnetii is thought to occur between wild deer and domestic livestock such as cows, sheep, and goats. Blood samples were collected from white-tailed deer throughout New York State in 2009 and 2010 and examined for anti-C. burnetii phase II antibodies via indirect microimmunofluorescence assays. Exploratory spatial cluster analysis revealed a lack of significant clustering of C. burnetii-seropositive deer. Logistic regression analysis revealed a significant association between the C. burnetii serostatus of deer and sex, percent agriculture, shrub, and forest cover, and townships with more than 10 bovine herds. A lack of significant association was revealed between the serostatus of deer and the year of sampling, soil type, percent wetland and open water cover, total annual precipitation, and townships with more than two sheep or goat herds. Because four different land cover types were associated with a higher probability of C. burnetii seropositivity, it is likely that land cover is not a discriminating factor in C. burnetii exposure. This is probably because C. burnetii environmental contamination is widespread and not localized to certain cover types. The social behavior of male deer may contribute to the lack of spatial clustering. Bucks typically travel over greater distances, which leads to a greater variety of encountered environments and a greater chance for exposure to C. burnetii. Because increasing agricultural land cover and townships with greater than 10 bovine herds are associated with an increased probability of diagnosing a seropositive deer, it appears likely that transmission of C. burnetii between domestic livestock and white-tailed deer may occur.