ANFS332 Lecture Notes - Lecture 27: Dirofilaria Immitis, Microfilaria, Hematophagy
27 Nov 2016
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Heartworm: heartworm is caused by a roundworm, dirofilaria immitis. Example of a filarial worm or small thread like worm: leading host is the dog but it can also infect cats, wolves, coyotes, raccoons, and foxes. As the embryo elongates, the surrounding membrane stretches to form an enclosing sheath. At birth, the membrane is lost and the embryo appears in the blood as a sheathless microfilariae: microfilaria, the young worms called microfilariae circulate in the blood stream of the dog. These worms must infect a mosquito in order to complete their lifecycle. Lifecycle ii: mosquitoes become infected when they blood feed on the sick dog. If the worms have infected an unsuitable host such as a human the worms usually die at this point: the worms burrow into the skin where they remain for 3-4 months and continue to mature. The fourth stage juveniles attain lengths up to 25 mm.
