FELINE HEARTWORM DISEASE

The recognition of heartworm (Dirofilaria immitis) infection in cats is increasing. In general, clinical signs displayed by cats are vague and can easily be confused with other respiratory or gastrointestinal disorders. As more data are gathered on feline heartworm disease, it is becoming apparent that cats respond to heartworms in a fashion uniquely different from dogs. Therefore, diagnostic and therapeutic methods that have been extrapolated from canine heartworm disease require modification to be applied to cats. Although no adulticide or microfilaricide drugs or preventives have been approved by the Food and Drug Administration, literature that describes treatment methods is becoming available. Because of the toxicity of thiacetarsamide sodium in cats, symptomatic, supportive treatment may be most appropriate for elimination of adult worms. As with dogs, the macrolide antibiotics (ivermectin and milbemycin oxime) seem to be efficacious as microfilaricides and preventives.