February is national heart health month, and the perfect time to talk about heart health in people and our pets. One significant issue for pets is a disease called heartworm, caused by foot-long worms that live in the heart, lungs, and associated blood vessels of affected pets. These worms can cause severe lung disease, heart failure, and organ damage, and when not detected, are usually fatal.
Heartworm disease affects dogs, cats, and ferrets. The worms also live in wolves, coyotes, foxes, and sea lions. And rarely, heartworms have even been found in humans.
Mosquitoes transmit many diseases, and even play a role in the transmission of heartworms. The American Heartworm Society (AHS) and the Niagara Frontier Veterinary Society (NFVS) note that adult female heartworms living in infected dogs, foxes, coyotes, or wolves produce microfilaria, which are microscopic baby worms that circulate in the animals’ bloodstreams.
When mosquitoes feed on the blood of these infected animals, they pick up microfilaria. Within 10 to 14 days, they mature and develop into infective stage larvae. When mosquitoes then bite another animal, these larvae are deposited onto the animal’s skin, ultimately entering their new hosts through the wound created by the mosquito’s bite. The larvae then spend the next six months maturing into adult heartworms. Upon reaching maturity, heartworms can live for five to seven years in dogs, and for two to three years in cats. Heartworm in ferrets can be rapidly progressive and fatal.
Heartworm symptoms can vary depending on the type of animal that is infected. Infected dogs may exhibit few or no symptoms in the early stages of the disease, only gradually showing symptoms as the infection persists. Such symptoms include mild persistent cough, reluctance to exercise, fatigue after moderate activity, decreased appetite, and weight loss. As heartworm progresses, dogs infected with the disease may develop swollen bellies due to excess fluid in their abdomens. Dogs infected with large numbers of heartworms may develop sudden heart blockages, which can lead to cardiovascular collapse, threatening the dog’s life.
Cats may exhibit subtle or dramatic symptoms of heartworm. Coughing, asthma-like attacks, periodic vomiting, loss of appetite, and weight loss are some of the elusive symptoms of heartworm in cats. But some cats may struggle to walk, experience fainting spells, or have seizures as a result of heartworm. Sometimes, the first sign of heartworm in cats is abrupt collapse or sudden death.
Ferrets with heartworms may seem constantly tired with shortness of breath even after just a few minutes of activity. They may have fluid buildup in their abdomens due to heart failure and blocked blood vessels.
Pet owners should have their pets tested for heartworm every 12 months and administer heartworm preventive every month, even here in Western New York. Learn more at www.heartwormsociety.org and www.nfvs.us.
The Niagara Frontier Veterinary Society is comprised of more than 75 animal hospitals and 200 veterinarians in Erie and Niagara Counties, New York. It exists to advance public awareness and understanding of proper pet health care, veterinary services, and the veterinary profession.
