FELINE HEARTWORM DISEASE

FELINE HEARTWORM DISEASE

Heartworm disease is caused by a parasite named Dirofilaria immitis. Heartworms are most commonly found in dogs, but now are known to also infect cats and other mammals. The adult heartworms live in the heart and major arteries of the lungs where they interfere with the function of the heart and lungs. The adult heartworm lives for 1-2 years in the cat, compared to 4-5 years in the dog..

TRANSMISSION. Heartworms can only be transmitted from one animal to another by mosquitoes. Once a bite occurs and the immature heartworms are deposited under the pet’s skin, they begin migrating through the tissues, eventually making their home in the heart and lungs where they mature into adult heartworms. Heartworms can occur in cats kept totally indoors if an infected mosquito should enter the house.

HEARTWORMS IN CATS IS A SERIOUS DISEASE. Whereas dogs can live with quite a few heartworms in the heart, because of their smaller size heart, 2-3 adult heartworms can be fatal to the cat.

SIGNS OF HEARTWORMS IN CATS. Clinical signs of heartworm disease in cats are quite variable. Many cats do not show any signs of heartworm disease until they die. In some acute cases, death may come so rapidly that there is insufficient time to make the diagnosis or provide any type of treatment. There are cases reported where the cat can appear clinically normal one hour before death. However some cats will show such signs as vomiting, coughing, & difficult breathing. Coughing may be intermittent or occur in severe, sudden attacks that take place days apart.

DIAGNOSIS. Clinical signs of heartworm are very similar to several other cat diseases. The diagnosis is confirmed with a combination of radiographs, ultrasound, and blood testing. We recently diagnosed a cat in our office by using the blood test. This cat presented to us with a history of a mild cough that had progressively worsened over several weeks.

TREATMENT. Treatment of heartworms in cats is not nearly as successful as in dogs. Treatment is complicated by the fact that after even one heartworm is killed in the heart, it can lead to an arterial blockage that has the potential to be fatal. Blood vessels in the cat are so much smaller than larger dogs creating much more risk while the dead heartworm is being removed from the body. Another one of the major problems is that no clinical signs are observed in many cases until close to death. What treatment we can employ is targeted at controlling clinical signs to the best of our ability.

PREVENTION. Since treatment is not very successful, prevention is very important. Even cats kept totally indoors can become infected from a mosquito in the house. Fortunately, heartworm preventives are available to be given to the cat once each month and we strongly recommend its use for all cats. Talk to your veterinarian bout the type of feline heartworm preventative he or she recommends.