D. immitis

Dirofilaria immitis, the heartworm or dog heartworm, is a parasitic roundworm that is spread from host to host through the bites of mosquitoes. The heartworm is a type of filarial worm, a small thread-like worm, that causes filariasis. The definitive host is the dog, but it can also infect cats, wolves, coyotes, foxes, and other animals, such as ferrets, sea lions and even, under very rare circumstances, humans.