BackgroundVector-borne diseases exert a global economic impact to the livestock industry. Understanding how agriculture practices and acaricide usage affect the ecology of these diseases is important for making informed management decisions. Theileria cervi is a hemoprotozoan parasite infecting white-tailed deer (Odocoileus virginianus) and is transmitted by the lone star tick, Amblyomma americanum. The purpose of this study was to determine if acaricide treatment decreased hematozoan prevalence in farmed white-tailed deer when compared to geographically-close wild deer or altered the genotypes of T. cervi present.ResultsWe compared prevalence of T. cervi in 52 farmed adult white-tailed deer which were regularly treated with permethrin and ivermectin, 53 farmed neonates that did not receive treatment for vector control, and 42 wild deer that received no form of chemical vector control. Wild deer had significantly higher prevalence of T. cervi than farmed deer. Additionally, no neonate fawns tested positive for T. cervi, and we found that age was a significant predictor of infection status. We found no difference in genotypic variation in T. cervi isolates between adjacent herds of farmed and wild white-tailed deer, although a divergent genotype X was identified. Chronic infection with T. cervi had no significant effects on mortality in the white-tailed deer.ConclusionsWe found significantly lower prevalence of T. cervi infection in farmed (40%) compared to wild white-tailed deer (98%), which may be due to the inclusion of chemical vector control strategies. More work is needed to determine the implications, if any, of mixed genotypic infections of T. cervi, although we found no significant effect of infection with Theileria on mortality in farmed deer. Theileria infection does sometimes cause disease when an animal is stressed, immunosuppressed, or translocated from non-endemic to endemic regions.

The white-tailed deer (Odocoileus virginianus) is the most economically important big game mammal in North America and Florida. This 12-page fact sheet written by Raoul K. Boughton, Bethany Wight, Samantha Wisely, Karen Hood, and Martin B. Main and published by the UF/IFAS Department of Wildlife Ecology and Conservation provides an overview of the various subspecies of white-tailed deer with populations in Florida and describes their history, biology, and management.https://edis.ifas.ufl.edu/uw121

The Eastern equine encephalitis virus (EEEV) causes Eastern equine encephalitis (EEE) disease in birds, humans, horses, and other animals in the eastern United States, including Florida, which is especially receptive to the virus because of its freshwater hardwood swamps and wetlands, which provide good niches for the mosquito vectors of the disease. This 5-page fact sheet written by Samantha Wisely and Karen Hood and published by the UF/IFAS Department of Wildlife Ecology and Conservation describes the disease and includes strategies for limiting its spread. http://edis.ifas.ufl.edu/uw453