Tick-borne pathogens and disease in dogs on St. Kitts, West Indies.

Between 2009 and 2011, we conducted a case-control study of ticks and tick-associated pathogens affecting dogs on the island of St. Kitts, eastern Caribbean, including 55 cases of clinically suspected tick-borne disease (TBD) and 110 presumably healthy animals presented for elective surgeries. Rhipicephalus sanguineus caused year-round infestations of dogs, and 36% of the dogs in the study were infested at the time of examination. Overall, 62% of suspected TBD cases and 24% of presumably healthy dogs tested positive by PCR for infections with: Anaplasma platys (0% and 4%), Babesia canis vogeli (20% and 6%), Babesia gibsoni (18% and 5%), Ehrlichia canis (35% and 7%), and Hepatozoon canis (5% and 2%). Co-infections were documented in 15% of these PCR-positive dogs. Antibodies against A. platys or E. canis were noted in 36% of the dogs. Thrombocytopenia was the most common sign of infection, followed by anemia. This is the first detection of A. platys, B. canis vogeli, or H. canis on St. Kitts and the first detection of B. gibsoni in the Caribbean. We conclude that tick-borne pathogens of dogs are highly prevalent in this region and may present in dogs that appear healthy, in spite of hematologic abnormalities that may increase surgical risk.