Biology

Dogs as Sentinels of Vector-Borne Disease Risk in Kentucky

Dogs have been shown to be important reservoir hosts for a wide variety of emerging and re-emerging vector-borne pathogens of humans. However, surprisingly few studies have been conducted to determine the prevalence of these pathogens in canine populations in the U.S.A. Previous studies from our lab showed a high prevalence of Trypanosoma cruzi, the etiological agent of Chagas’ disease, in raccoons and opossums from Warren and Barren counties of Kentucky. These studies were the first to document the presence of T. cruzi in our state, however, a variety of studies have shown that T. cruzi is well established in wild mammal populations across the southern U.S.A. Domestic canines are regarded as natural sentinels of transmission of T. cruzi, since seropositivity in an owner’s dog suggests the presence of the Chagas’ disease vector, Triatoma spp., in or around the household. However, the potential for transmission of this important protozoan pathogen to domestic dogs or humans in the U.S.A. has not been well studied. In collaboration with the Breathitt Veterinary Lab in Hopkinsville, Kentucky, we have begun to investigate the prevalence of Trypanosoma cruzi in canine populations of central and western Kentucky via serological assays and polymerase chain reaction. In addition, we have used Canine SNAP 4Dx tests (Idexx Laboratories, Inc., Westbrook, Maine) to determine the prevalence of four additional vector-borne pathogens: Dirofilaria immitis (canine heartworm), Anaplasma phagocytophilum (anaplasmosis), Borrelia burgdorferi (Lyme disease), and Ehrlichia canis (ehrlichiosis). Results to date reveal a surprisingly high seroprevalence of 17.1% for T. cruzi, a 4.5% prevalence for D. immitis and E. canis, and 0.56% for A. phagocytophilum and B. burgdorferi (the agent of Lyme disease). We believe that further studies are urgently needed to fully evaluate the role that canines might be playing as reservoir hosts for these as well as other vector borne diseases in the southeastern U.S.A.