Tropical lymphedemas--control and prevention.

n engl j med 366;13 nejm.org march 29, 2012 1169 Wuchereria bancrofti (and, in Asia, Brugia malayi and B. timori), which is transmitted by mosquitoes. The second principal cause is podoconiosis. Lymphatic filariasis is endemic in some 72 countries throughout the tropics (see map), and an estimated 1.39 billion people live in areas of risk.1 An estimated 40 million people have stigmatizing and disabling clinical manifestations of the infection: 15 million have elephantiasis, and some 25 million men have genital swelling, usually scrotal hydrocele.1 The current strategy for stopping transmission is the annual mass administration of donated drugs — albendazole and ivermectin in areas of Africa where onchocerciasis is coendemic, and diethylcarbamazine and albendazole elsewhere. The Global Program to Eliminate Lymphatic Filariasis (GPELF), begun in 2000, is aimed at eliminating transmission of the infection and reducing associated illnesses. Through annual mass distribution of drugs, substantial progress has been made in 12 years toward the elimination target set by the GPELF, with about 466 million people treated in 2010. The economic benefits accrued through the program from 2000 through 2008, including the ancillary benefits of deworming and the impact on scabies, have been calculated at $24 billion. Costs per year for control of lymphatic filariasis range from $0.06 to $1.00 per person, depending on the setting; as with other neglected tropical diseases, costs of preventive chemotherapy are general ly less than $0.50 per person per year. Therefore, prevention of lymphatic filariasis ranks among the most cost-effective global health interventions, along with deworming and onchocerciasis prevention, as measured in cost per disability-adjusted life-year averted.2 Lymphatic filariasis is one of 17 neglected tropical diseases that afflict the world’s poorest people, but another even more neglected condition causing elephantiasis has been highlighted in recent years — podoconiosis, which affects some 4 million people in Africa, Latin America, and a few areas of Asia3 (see map). For many years, podoconiosis was relegated to the small print of even specialist tropical medicine Tropical Lymphedemas — Control and Prevention