Chicken Anti-D. immitis Polyclonal antibody for WB, IP, ELISA, ICC, IF. Heartworm is a parasitic roundworm (Dirofilaria immitis) that is spread from host to host through the bites of mosquitoes. The heartworm is a type of filaria, a small thread-like worm. The definitive host is the dog but it can also infect cats, wolves, co