Tick Burdens in a Small-Mammal Community in Virginia

Abstract

Virginia has seen dramatic increases in reported cases of Lyme disease and Rocky Mountain spotted fever, but basic knowledge on the community ecology of these tick-borne diseases is poor. We examined the tick burdens of 5 small-mammal species in northwest Virginia from October 2011 to December 2012. We live-trapped individuals, quantified the tick burdens, assessed the burden structure, and tested a subset of the ticks for tick-borne pathogens. We found the tick burdens to be composed predominantly of Ixodes scapularis (Black-Legged Tick), and Ixodes sp. ticks, with Amblyomma americanum (Lone Star Tick) and Dermacentor variabilis (American Dog Tick) also present at lower densities. We detected Borrelia burgdorferi (prevalence 15%), Rickettsia spp. (4%), Anaplasma phagocytophilum (4%), and Hepatozoon spp. (1%). Black-Legged Ticks, a species which has shown range expansion in recent decades, tested positive for B. burgdorferi (17%) and for multiple pathogens in individual ticks. For better predictions of tick-borne disease risk across the Mid-Atlantic region, we recommend tracking changes in tick communities by continuous monitoring of tick burdens, densities of questing ticks, and prevalence of tick-borne pathogens.