Heart worm in dogs is caused by what?

The heartworm in dogs is caused by a parasite called Dirofilaria immitis. It is a long, thin, white worm that lives in the heart, lungs, and blood vessels of dogs. The parasite is transmitted to dogs by infected mosquitoes. When a mosquito bites an infected dog, the mosquito ingests the heartworm larvae. These larvae develop into infective larvae inside the mosquito and are then transmitted to other dogs when the mosquito bites them. The infective larvae travel to the dog's heart, where they mature into adult worms. The adult worms can grow up to 12 inches long and can live in the dog's body for up to 7 years. Heartworm disease is a serious condition that can lead to heart failure and death.