Filariasis is caused by several round, coiled and thread-like parasitic worms that belongs to the family filaridea. These parasites penetrate the skin either   their own or through the opening created by mosquito bites to reach the lymphatic system.

Symptoms

Lymphatic filariasis infection involves asymptomatic, acute, and chronic conditions. The majority of infections are asymptomatic, showing no external signs of infection, although their blood is positive for microfilaria. This stage may lasts for months. Acute episodes of local inflammation involving skin, lymph nodes and lymphatic vessels. Chronic condition shows  oedema with thickening of the skin and underlying tissues.

It usually affects the lower extremities. However, the arms, vulva, breasts and scrotum (causing hydrocele formation) can also be affected. The oedema  in the extremities, breast or genital area can result in the part becoming  several times its normal size and is due to blockage of the vessels of the lymphatic system.