Filaria, << fih LAIR ee uh, >> is a long, threadlike roundworm that lives as a parasite in the bodies of human beings and animals. Filariae are commonly found in tropical and subtropical countries. The male worm is shorter than the female, and it has a curved tail.
The larvae (young worms) are born alive. They can be seen in the blood near the body surface of the host (the animal in which the larvae live). When a bloodsucking fly or mosquito bites an infected person, it takes up the larvae with the blood. The larvae develop in the mosquito’s or fly’s head near the mouth. Then when the insect bites another animal, the larvae enter the wound and infect a new host.
Wuchereria bancrofti is a filaria harmful to human beings. It is found in Africa, South America, and the Far East. The adult worms live in the lymph, a body fluid (see Lymphatic system). When the worms block the flow of lymph, a disease called elephantiasis, or lymphatic filariasis, results. This disease is characterized by severe swelling of the limbs, usually the legs (see Elephantiasis). Wuchereria bancrofti can be eliminated by controlling the mosquitoes that carry the larvae. Other kinds of filariae infect such animals as cattle and dogs.
See also Manson, Sir Patrick; Roundworm.
