HOW IS HEARTWORM DISEASE SPREAD?     

1. The cycle begins when a mosquito bites a heartworm-infected animal and picks up microfilariae, which are immature heartworms that circulate in the infected animal’s bloodstream.

2. During the next two to three weeks, the microfilariae develop into infective larvae within the mosquito.

3. When the mosquito feeds again, it will transmit the infective larvae into a healthy animal. The larvae develop into adult heartworms over the next six to nine months while migrating to the animal’s heart.

4. Once inside the animal’s heart, the adult worms can grow up to 14 inches long and can cause significant damage to the lungs.