The State of Heartworm Incidence in the U.S.

The 2019 AHS Heartworm Incidence Survey shows that heartworms maintain a stubborn hold in the United States.

Chris DukeDVM
Doug CarithersDVM

Changes in weather patterns. Lapses in preventive medication compliance. Pet relocation. These factors and more were cited in a recent survey of U.S. veterinarians as factors contributing to the rise and fall of heartworm incidence in their practice areas.
 
To help veterinary professionals, shelter personnel, and pet owners understand heartworm trends in their areas, the American Heartworm Society (AHS) began tracking U.S. heartworm incidence in January 2002. Since then, the AHS Heartworm Incidence Survey has been conducted every 3 years, using heartworm testing data submitted by veterinary practices, reference laboratories, and animal shelters. Following the analysis of survey results, a U.S. heartworm incidence map is generated to provide a visual representation of the spread and severity of heartworm infections.