The American Heartworm Society (AHS) has released its 2007 guidelines for the diagnosis, prevention and management of cat heartworm infection. The most notable update is information on the newly-defined, heartworm-associated respiratory disease.
According to the AHS, some cats never develop clinical signs of heartworm infection, but even a small number of worms can be life-threatening. Signs of heartworm infection, such as coughing, vomiting and lethargy among others, usually develop either in the first stage when the heartworms enter a blood vessel and are carried to the pulmonary arteries, or in the second stage when the adult heartworms die.
The AHS reported that the signs associated with the first stage of heartworm-associated respiratory disease are often misdiagnosed as asthma or allergic bronchitis.
Another highlight of the updated guidelines is information on interpreting test results. Heartworm infection is harder to diagnose in cats than in dogs and easy to overlook, according to the AHS.
Diagnostic tests have limitations, so test results that are negative for heartworms do not necessarily rule out an infection, the AHS said. Antigen tests, for example, detect only adult female or dying male worms. Immature or male-only worm infections are rarely detected.
Click here to view the new guidelines on cat heartworm infection.