Dog heartworm

Dirofilaria immitis

Mosquito (Aedes aegypti) The mosquito, Aedes aegypti is a vector of dog heartworm - it transmits the parasite from one host to another.

Dog heartworm, is a dangerous roundworm (nematode) parasite that often results in heart failure and pulmonary artery complications for infected dogs.

Heartworm is prevalent throughout most of Australia and has a broad distribution around the world. Fortunately it is easily treated through the regular application of drugs.

The adult worms in the heart and pulmonary artery of an infected dog produce larvae, called microfilariae, which circulate throughout the bloodstream. These are taken up by a mosquito (typically species of the genus Aedes) when it feeds on the dog and the parasite develops further within the insect.

To complete the lifecycle, the worms migrate to the mouthparts of the mosquito where they escape and enter a new dog host via the wound caused by the mosquito feeding. After several months the juvenile parasites enter the peripheral blood vessels from the tissues of the host, then enter the general circulation and mature in the pulmonary arteries and right-side of the heart.

Infections have been detected in humans, who can develop a lung condition called pulmonary dirofilariasis. Fortunately for us, symptoms are generally mild and the parasites are not able to complete their life cycle in humans.

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