fifth disease

filariasis A parasitic disease caused by the African eye worm, a microscopic thread-like worm. The adult worms can only live in the human lymph system. Lymphatic filariasis affects people in the tropics and sub-tropics of Asia, Africa, the Western Pacific, and parts of Central and South America. The disease spreads from person to person by mosquito bites. The microscopic worms travel to the lymph vessels and grow into adults. The adult worms mate and release millions of microscopic worms into the blood. The disease usually is not life threatening, but it can cause permanent damage to the lymphatic system and kidneys. Because of the damage to the lymphatic system, fluid collects and causes swelling (known as lymphedema) in the arms, breasts, legs, and, for men, the genital area. Also known as lymphatic filariasis. See also lymphedema.