WHAT ARE HEARTWORMS?
Heartworms are parasitic worms that may reside, as their name implies, inside their host’s heart, but much more commonly are found in the host’s lungs. The heartworm's life cycle and infestation is longer and more complicated than other common worms. Young heartworms incubate and grow inside mosquito hosts, and are transmitted to a new host when the mosquito bites a human, a cat or — in most cases — a dog. The heartworms spend several months maturing inside the body of their hosts, during which time the host typically is asymptomatic. Early symptoms can include coughing and fatigue, and may progress to extreme weight loss, coughing blood and congestive heart failure.