Every three years, the American Heartworm Society (AHS) gathers data on heartworm testing to understand the impact heartworm is having nationwide, as well as in specific regions. Testing data from thousands of veterinary practices and shelters is used to create a detailed map showing the average number of heartworm-positive cases per clinic. 46 reported HW positive cases in dogs in Brevard County in January & February. 6 cats reported HW positive last year, one so far this year in Brevard County.