Feline Heartworm Guidelines updated by the AHS

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Addressing the “persistent” underdiagnosis and undermanagement of heartworm disease in cats is the driving force behind recent guidelines updates from the American Heartworm Society (AHS).

The AHS Feline Heartworm Guidelines for veterinarians, finalized following a scientific review by parasitology, cardiology, and clinical practice experts, provides revised guidance on heartworm screening, mosquito control, and treatment options for heartworm-positive cats.

The AHS outlines four main reasons for heartworm testing in cats: aiding diagnosis in symptomatic cats, monitoring heartworm-positive cases, establishing baselines before preventive treatment, and assessing heartworm risk in specific areas.

“While dogs are routinely screened for heartworms during annual check-ups, testing in cats has primarily been limited to cases when a veterinarian suspects heartworm infection based on a cat’s clinical signs,” says AHS president Jennifer Rizzo, DVM. “With so few cats tested, it has been difficult for veterinarians to get a handle on the true incidence of heartworm in cats—even though cats are at risk wherever heartworm infection occurs in dogs.”

The revised guidelines advise using both antigen and antibody tests, with antigen tests performed on heat-treated serum to improve accuracy. Notably, antigen-antibody complexes in feline samples are more likely to yield positive results after heat treatment than canine samples.

Additionally, the AHS continues to recommend cats be on year-round heartworm prevention with a macrocyclic lactone product. This revision aims to reduce the risk of mosquitoes in the environment rather than just on cats themselves.

“As an organization dedicated to reducing the incidence of heartworm disease and its impact on pets, the AHS has long been concerned about the underdiagnosis and undermanagement of heartworm disease in cats,” says Dr. Rizzo. “Fortunately, we now have scientific information that supports a more proactive approach to heartworm diagnosis, as well as greater specificity in prevention and treatment approaches.”

For more information, visit the AHS website.

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