The American Heartworm Society’s newly updated canine heartworm guidelines provide spectrum-of-care advice for veterinarians treating dogs under less-than-ideal circumstances.
“The goal of this update was to ensure that our recommendations continue to be both scientifically grounded and practical for veterinarians to implement,” said the American Heartworm Society’s president, Dr. Jennifer Rizzo. “The update includes changes to our guidance, as well as reinforcement of key points that remained unchanged.”
The guidelines, which were reviewed and authored by parasitology, cardiology and clinical practice experts, include these key points and takeaways:
- Wildfires, hurricanes and other events caused by environmental and climate changes have led to animal shelters relocating microfilaremic dogs. Infections have been diagnosed in all 50 states and around the globe.
- Since female heartworms do not mature sexually until Day 120 post-infection, microfilariae do not circulate in dogs until six to nine months post-infection.
- The organization and the Federal Drug Administration recommend year-round administration of FDA-approved heartworm preventive drugs.
- The organization recommends FDA-approved isoxazolines and EPA-approved mosquito repellents to help prevent heartworm’s spread.
- Macrocytic lactone-resistant heartworms have been documented. Poor compliance with veterinary recommendations was the most common cause.
- All dogs over 7 months old should be screened annually with antigen and microfilaria tests.
- Dogs over 7 months old should be tested before starting on a preventive.
- All positive antigen tests should be confirmed by additional testing before treatment begins.
- Dogs exhibiting significant clinical signs must be stabilized before starting heartworm treatment.
- The only FDA-approved adulticidal drug is melarsomine.
- Activity restrictions are critical during heartworm treatment to minimize cardiopulmonary complications.
- Four-week doxycycline treatment before the use of melarsomine is recommended to reduce the pathology associated with dead heartworms.
“Heartworm disease in dogs continues to be far too common despite the availability of highly effective medications to prevent and treat it,” Dr. Rizzo said. “Our hope is that the updated guidelines can provide the practical and proven support veterinarians need to significantly reduce the rate of heartworm disease.”
The resource also includes a spectrum-of-care section, which the organization stated is “intended for use in clinical situations when a practitioner is unable to follow the optimal treatment protocol for heartworm-positive patients and needs access to information on efficacy and complication rates.”
The complete guidelines are at heartwormsociety.org/guidelines.