23. Tropical Diseases Lacking Adequate Control Measures: Dengue, Leishmaniasis, and African Trypanosomiasis

Abstract

Several insect–borne tropical diseases responsible for epidemic outbreaks still lack effective control measures, according to the World Health Organization. Dengue, leishmaniasis, and African trypanosomiasis (sleeping sickness) together result in more than 10 million new infections each year, but treatment is either unavailable or based on antiquated therapies. Vector control is most promising for the tsetse fly, the carrier of sleeping sickness, but requires a sustained organizational response.

All three diseases affect substantial populations. Among them, dengue is the leading cause of pediatric deaths; leishmaniasis is fatal, particularly to males between the ages of 5 and 29; and African trypanosomiasis disproportionately kills adult men?and all take a significant economic toll. The impact of dengue can be measured in terms of medical costs and lost productivity as well as loss of tourist dollars. For leishmaniasis, the cost of both drugs and drug delivery is especially high. The economic impact of sleeping sickness is two–fold: constraining human labor and threatening food supplies when animals succumb to a form of the disease.

Given that there is no specific treatment for dengue and the drugs used to combat leishmaniasis and African trypanosomiasis are quite toxic, the current challenge is to make better use of the tools already available as well as to develop better drugs. An important weapon in the disease–fighting arsenal is a sustainable, long–term surveillance system capable of providing early warning of impending outbreaks. In the case of leishmaniasis and sleeping sickness, early and accurate diagnosis and treatment are essential.