This is a disease that occurs as the result of a filaria entering the blood system. A filaria, is a long, thread-like 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.
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 and when the worms block the flow of lymph, a disease called elephantiasis results. This disease is characterised by severe swelling of the limbs, usually the legs. Wuchereria bancrofti can be eliminated by controlling the mosquitoes that carry the larvae. Other kinds of filariae infect such animals as cattle and dogs.