The heartworm life cycle begins when a mosquito bites an infected animal and ingests tiny heartworm larvae along with the animal’s blood. Coyotes, wolves, foxes, and ferrets can also develop heartworm disease in addition to dogs and cats. Next, the larvae develop into an infective stage inside the mosquito. When a heartworm disease-carrying mosquito bites your pet, it transmits the larvae that develop for approximately two months in your pet’s tissue. Afterwards, developing and mature adult heartworms can be found in the bloodstream, heart, and lungs. They can also produce tiny heartworm larvae that is released into the blood and is picked up by mosquitoes who repeat the process again.