Epidemiology

Abstract

Lymphatic filariasis is a mosquito-borne disease that, in its advanced forms, can manifest as severe lymphedema, hydrocele, and elephantiasis. It is estimated that there are 1.3 billion people living in endemic areas in 81 countries and that 120 million people are infected. More than 90% of these infections are caused by W. bancrofti, for which humans are the only natural host. There can be potential acute manifestations of infection, particularly acute filarial lymphangitis and acute dermatolymphangioadenitis. The clinical manifestations of chronic lymphatic filariasis include lymphedema, elephantiasis, and hydrocele. Lymphedema management involves leg hygiene, early treatment of bacterial and fungal infections, elevation, and exercises. The chronic clinical manifestations of lymphatic filariasis lead to adverse psychological and economic consequences, making lymphatic filariasis one of the leading causes of disability and an impediment to economic and social development: Lymphatic filariasis is a mosquito-borne, neglected tropical disease that can cause lymphedema, hydrocele, and elephantiasis. The disease is second only to malaria for disability-adjusted life years. Lymphatic filariasis is endemic in Africa, Asia, the Indian subcontinent, the western Pacific Islands, focal areas of Latin America, and the Caribbean, particularly Haiti and the Dominican Republic. The distribution of lymphatic filariasis is highly focal within an endemic area. During a blood meal by the mosquito vector, larvae penetrate the skin and home to lymphatic vessels and nodes. Adult worms can live in the lymphatic vessels and produce microfilaria for 5-10 years. Acute manifestations of infection can include acute filarial lymphangitis and acute dermatolymphangioadenitis. The clinical manifestations of chronic lymphatic filariasis include lymphedema, elephantiasis, and hydrocele. These generally increase in frequency with age. Factors that favor the progression of filarial lymphedema to elephantiasis include repeated attacks of acute dermatolymphangioadenitis, the intensity of filarial transmission within a population, and the presence of the bacterial endosymbiont, Wolbachia. Lymphedema management involves leg hygiene, early treatment of bacterial and fungal infections, elevation, and exercises.