Lymphatic Filariasis (LF)

  • This is a disease of the tropics. It is caused by infection with any of several round, thread-like parasitic worms. The most common is infection with a parasite that lives in the lymph system.
  • Filariasis is caused by three types of parasitic worms: Wuchereria bancrofti, Brugia malayi, and Brugia timori
  • Long-term exposure and repeated infections can cause severe damage to the lymph system and seri-ous, debilitating complications. It is a leading cause of permanent and long-term disability world-wide
  • Wuchereria bancrofti, the most common filaria-sis parasite, is found in Africa, India, Southeast Asia, the Pacific islands, the Caribbean, and South America. The Brugia malayi and Brugia timori parasites are found in Southeast Asia.
  • Prevention centers on controlling mosquito populations in communities and avoiding mosquito bites.
  • Filariasis is spread from infected persons to uninfected persons by mosquitoes. Adult worms live in an infected person’s lymph vessels. The females release large numbers of very small worm larvae, which circulate in an infected person’s bloodstream. When the person is bitten by a mosquito, the mosquito can ingest the larvae. These develop in the mosquito and can then be spread to other people via mosquito bites. After a bite, the larvae pass through the skin, travel to the lymph ves-sels, and develop into adults, which live about 7 years. Then the cycle begins again.
  • Affected people frequently are unable to work because of their disabil-ity. This hurts families and communities. Poor sanitation in tropical and subtropical areas of the world, where the disease is common, has cre-ated more places for mosquitoes to breed and has led to more people becoming infected.