The Companion Animal Parasite Council (CAPC) has released its 2026 Pet Parasite Forecast, projecting continued expansion of vector-borne disease risk across the United States, including Lyme disease, ehrlichiosis, anaplasmosis, and heartworm. Based on analysis of more than 10 million veterinary diagnostic test results annually, the forecasts are intended to help veterinarians anticipate regional disease trends and guide prevention and testing strategies.

CAPC highlights expanding Lyme disease risk beyond traditional Northeast and Upper Midwest hotspots into parts of the Midwest, Appalachia, and the Northern Plains. Heartworm risk remains highest in the Southeast, with continued northward spread along major river and coastal corridors and emerging pockets in western states. Tick-borne ehrlichiosis and anaplasmosis are also expanding as tick species extend their geographic ranges, with year-round transmission possible in some regions.

The council emphasizes year-round parasite prevention, annual testing, and use of local surveillance data to inform care. Veterinarians are encouraged to use CAPC tools, including monthly 30-day parasite forecasts and real-time flea activity maps, to support regional risk assessment and client education. CAPC positions its forecasts as a One Health resource linking animal, human and environmental health trends.