Discussions about heartworm disease were once relegated exclusively to the dog owning segment of veterinary clientele. Today, an increasing number of veterinarians are extending heartworm disease awareness to owners of their feline patients. Heartworm in cats is not as rare as was once suspected. It is more difficult to diagnose than canine heartworm disease, and the illness poses a much greater threat to your cat’s lifespan. Fortunately, feline heartworm disease can be prevented.
How Do Cats Get Heartworm Disease?
Mosquitoes are the vectors that transmit heartworm disease to our pets. A mosquito feeds off of an animal that is infected with heartworm disease, and then bites your dog or cat to pass on the disease. Heartworms in cats and dogs are parasites. These parasites evolve through several life stages. In dogs, the concerning stage is the adult stage, during which the heartworms dwell in the dog’s heart. Heartworm in cats has life threatening consequences during the larval stage, when the heartworm larvae travel through a cat’s bloodstream and into the lungs. This results in the severe, and often fatal, respiratory disease.
The Symptoms of Heartworms in Cats
Feline heartworm disease is challenging to diagnose in cats because the signs of heartworms in cats are similar to those of feline asthma. These symptoms of heartworms are coughing and wheezing. Some cats may not cough or wheeze, displaying more generalized symptoms of heartworms that include lethargy and a decrease in appetite. In some tragic instances, cats show no symptoms of heartworms at all until they are the victims of sudden and unexpected death.
Diagnosis of Heartworm Disease In Cats
Diagnosing heartworm in cats is much more difficult than in dogs. The larvae that infiltrate a cat’s lungs cause inflammation. This can be seen on chest radiographs, but the pattern and appearance of the inflammation mimics those that accompany feline asthma. Dogs undergo a routine blood test each year to check for the presence of heartworm antigens, which are essentially markers that confirm the presence of adult heartworms. The parasite load of adult heartworms is much higher in infected dogs than in cats. Since heartworms in cats pose the greatest threat during the larval stages, a cat is in danger from the disease while harboring only minimal adult worms. This low number of adult heartworms in cats is not enough to display the necessary level of antigens to generate a positive test result. This means that a number of cats that are tested for heartworm disease generate false negative results.
The Dangers of Treatment
Even if a cat can be diagnosed through the presence of symptoms and a positive heartworm test result, treatment is also a greater challenge than it is in dogs. There is no currently approved treatment for heartworm disease in cats. This is because if a treatment is attempted, a severe inflammatory response occurs due to the sudden, mass die-off of a large number of larvae present in the pulmonary arteries of the cat’s lungs, resulting in fatal consequences. Instead, symptomatic treatment and inflammatory management with steroids are typically implemented to keep the cat comfortable for the duration. A heartworm preventative product is also administered to prevent reinfection. In some cases, the worms will gradually die off with age over a period of a few years, and these cats manage to survive the ordeal.
Prevention is Imperative
Ask your veterinarian about one of the monthly oral or topical heartworm preventatives for your cat. Some of these products also prevent other parasites, such as fleas, intestinal parasites or ear mites. While cats that venture outdoors have the highest risk for contracting heartworm disease, indoor cats are not immune. The occasional mosquito manages to sneak indoors through an opening door, window air conditioner vents, chimneys or tiny rips in window screens. Depending on your area of residence, your veterinarian may recommend the use of a preventative product throughout the year. Since you were interested in how cats get heartworm, find out more about heartworm in dogs.
