Recent studies have shown an increase in heartworm disease in dogs and cats in our area. Studies in the southern United States have shown exposure in 10% of indoor cats and 35% of outdoor cats, and confirmed infection in 5% of cats tested. This makes heartworm disease as prevalent as Feline Leukemia and FIV – the cat aids virus in some areas. Cats are more resistant to heartworm infection than dogs and the incidence of heartworm infection in cats is usually about 10 –20% of the dog infection level in a given area.
Animals are at increased risk of infection due to our highly mobile society. Many people travel with their dogs and cats to areas where heartworm disease is very prevalent. Even if you do not travel much, your neighbor might and mosquitoes can transmit the disease from pet to pet. Mosquitoes can live 2-3 weeks and one blood meal on an infected pet means that every pet they bite after that can become infected.
Cats generally have fewer worms than dogs do when they get an infection, but the size of their heart is smaller and it only takes one or two worms to cause severe damage and even death. Clinical signs of heartworm disease in cats can be very similar to respiratory or intestinal disorders leading to an underestimation of cats evaluated for heartworm disease.
Common clinical signs include respiratory problems (chronic cough, acute trouble breathing, increased respiratory rate and coughing up blood), chronic vomiting and occasionally central nervous system disorders, blindness, heart arrhythmias, anorexia, weight loss, and lethargy. Heartworm disease can also cause sudden death in cats with very little previous symptoms.
Treatment of heartworm disease in cats can cause severe side effects and even death in a high percentage of patients and is generally not recommended. Supportive care with steroids and restricted activity is usually the safest therapy.
Because heartworm disease can be fatal and difficult to treat in cats, we recommend putting your cats on a heartworm preventative monthly just like our canine patients. The topical preventative we recommend currently is Advantage Multi, which helps prevent heartworms, and also treats fleas, ear mites, and some intestinal parasites. Although testing is not required prior to starting Revolution, we recommend testing any cat that has shown signs of respiratory disease, intermittent vomiting, or weight loss.
Please talk to one of the doctors or staff at Woodland Vet Hospital if you have questions about heartworm disease in your cat or dog, or if you need to get them started on a prevention plan.