Latest Strategies for Prevention and Treatment AHS revises guidelines on heartworm for dogs
The American Heartworm Society (AHS) has released an updated version of its Canine Heartworm Guidelines on April 9, focusing on heartworm prevention, diagnosis, and treatment.
Year-Round Prevention Recommended
The AHS continues to advocate for the year-round use of macrocyclic lactone heartworm preventives as the foundation of heartworm management. The new guidelines also recommend using both FDA-approved isoxazolines and EPA-approved mosquito repellent products to kill mosquitoes and prevent heartworm spread. Previously, only EPA-approved products were suggested. These revisions are based on the latest research and aim to address common questions from veterinary practitioners.
Key Guidelines Highlights
Annual Testing
The AHS guidelines advise annual antigen and microfilaria testing for canine patients. Microfilaria testing is particularly crucial when the dog’s prevention history is unknown or if heartworm infection is suspected.
“Discrepancies between antigen and microfilaria test results are common,” the guidelines state. “If a dog is microfilaria-positive but shows no antigen, repeating the antigen test with a heat-treated blood sample can unmask blocked antigens for a more accurate result.”
Spectrum-of-Care Section
The guidelines now include a spectrum-of-care section for situations where the optimal heartworm treatment protocol isn’t feasible. This section covers:
- Procedures with fewer melarsomine injections
- Alternatives to melarsomine treatment
- Guidance for interrupted heartworm treatment
Dr. Jennifer Rizzo, AHS president, emphasizes the importance of these guidelines in providing scientifically backed information on treatment prioritization, efficacy, and complication rates.
Heartworm Incidence Survey
The AHS conducts a heartworm incidence survey every three years, with the latest data reflecting 2022 tests. Results show a rising trend in heartworm rates, particularly in Arkansas, the Carolinas, Georgia, Mississippi, and Texas. States with historically low heartworm rates, like Connecticut, Kansas, Massachusetts, North Dakota, Oregon, and Washington, also saw unexpected increases.
A January study in Frontiers in Veterinary Science by Banfield Pet Hospitals corroborated these findings, showing increased heartworm incidence in the Northwest and New England.
Importance of Education and Empathy
“These data points highlight the need for better consumer education, access to care, and consistent recommendations from veterinary teams,” said Dr. Rizzo. “With so few dogs consistently protected, cases continue to rise.”
Dr. Rizzo stresses the importance of education and empathy when discussing heartworm with clients. Understanding clients’ beliefs, budgets, and concerns is key to effective communication and prevention strategies.
Comprehensive Guidance
Sponsored by Boehringer Ingelheim, Elanco, Merck Animal Health, Zoetis, Ceva, and Idexx Laboratories, the updated Canine Heartworm Guidelines are the most comprehensive and rigorously researched resource on heartworm epidemiology, biology, prevention, and treatment.
The AHS offers various resources for veterinary practices, including:
- Interactive apps
- Incidence maps
- Posters
- Heartworm images
- Heartworm life cycle diagram
- Social media tools
- Heartworm preventive waiver
These resources are designed to support veterinary practices in effectively managing heartworm prevention and treatment.
