AffectedAnimals:
Dogs and cats. Overall, cats are infected by heartworms much less commonly, even in areas in which heavily infected dogs are present. Male cats tend to be infected more commonly and have a larger worm burden than female cats, mostly because male cats spend more time roaming outside and have less resistance to infection than female cats. Cats that spend significant amounts of time outside, especially in mosquito-populated areas, are at increased risk for developing heartworm infection.

Overview:
Heartworm disease is a serious infection of the heart by parasitic worms called Dirofilaria immitis. It is not uncommon for infected cats to develop fatal respiratory and cardiac-related complications. Other cats, however, will have only minor symptoms such as vomiting, or no clinical signs at all.

Heartworm disease is spread by mosquitoes, which inject the larvae from the heartworm parasite into the skin when they bite. Thus, outdoor cats are at higher risk of infection, as they have an increased exposure to mosquitoes. Certain sections of the world have heavier populations of heartworm disease than others; cases of feline heartworm have been found most frequently in the eastern and mid-western states and in California.

Because of increased availability of tests to detect feline heartworms and a greater awareness of the disease, more veterinarians are able to diagnose the disease. Depending on the severity of the infection, there are a number of methods for treatment, including medications to alleviate the symptoms, drugs to kill the worms, and surgery.