Filariasis is a tropical disease caused by a parasite in your body due to bite of an infected mosquito. It affects the lymph channels & lymph nodes in the body leading to a disease called Elephantiasis in which there is an abnormal enlargement of body parts specially legs. It can also involve non-lymphatic areas like eyes, kidneys & lungs. This disease is commonly seen in India, Asia, Africa & South America. This is a useful test to detect Chronic lymphatic filariasis and to map the prevalence of disease.