Filariasis larvae can sometimes be detected in blood. Those most at risk are people who live in or stay for a long time in tropical areas where the disease is common. Short-term tourists rarely get filariasis. Getting an infection with symptoms usually requires several mosquito bites over a long period of time. This can lead to severe disfigurement, decreased mobility, and long-term disability.
Testicular hydrocele is a disfiguring enlargement of the scrotum.
At least 120 million people in 73 countries worldwide are estimated to be infected with filariasis parasites. The most widespread is Wuchereria bancrofti , which affects about 100 million people in Africa, India, Southeast Asia, the Pacific islands, South America, and the Caribbean. The Brugia malayi and Brugia timori parasites affect about 12 million people in Southeast Asia. Lymphatic filariasis is among the world's leading causes of permanent and long-term disability. The number of infected persons is increasing worldwide, due in large part to unchecked urbanization in many areas where the parasite is common.