Heartworm Disease
posted: Apr. 05, 2019.
Heartworm Disease
Heartworm disease is caused by Dirofilaria immitis, a worm that lives out its adulthood in the blood vessels of the heart and lungs of dogs.
This disease is spread by mosquitoes. Mosquitoes take a blood meal from an infected dog, picking up microfilariae (baby worms) in the blood. They then transmit these microfilariae to the next dog the feed on. If the dog is on heartworm prevention, these microfilariae are killed off. If the dog is not on prevention, the microfilariae migrate eventually to the heart and lungs where they can live 5-7 years and grow to an adult length of 6-12 inches. The longer the adult worms are in place, the worse the damage they cause to the surrounding heart and lung tissue. Eventually, with enough worms, they can cause heart failure or cardiovascular collapse.
Prevention is the best option for heartworm disease. Treatment of the disease is not only expensive, but also involves risk for the pet. Preventive medication, including Heartgard Plus, kill off the microfilariae before they have a chance to mature and cause damage to your dog. Annual testing is recommended for every dog - it takes up to 7-9 months after microfilariae enter the bloodstream in an untreated pet for a based heartworm test to be able to detect the antigen released by adult female worms. It is also recommended to keep your pet on prevention year-round (12 months of the year). Even though Colorado has relatively low rates of heartworm disease, dogs coming from other states can also carry heartworm disease with them.
*Heartworm disease can be carried by cats, coyotes, foxes, and wolves, although dogs are the primary host.
References:
https://www.heartwormsociety.org/pet-owner-resources/heartworm-basics
https://www.heartwormsociety.org/veterinary-resources/incidence-maps
https://www.heartwormsociety.org/veterinary-resources/client-education/heartworm-life-cycle