Life Cycle

Figure 1. Diagram of heartworm life cycle from Hill’s Atlas of Veterinary Clinical Anatomy
Canine heartworm is a 23 to 30 cm long worm that resides inside the heart of the dog. The female produces baby heartworms called microfilariae which spread out through all the blood vessels of the dog. When mosquitoes feed on infected dogs, they suck in blood and the baby heartworms. They molt three times inside the mosquito producing L3 (more…)