Trypanosomiases

Abstract

The human trypanosomiases are vector‐borne tropical diseases that occur in tropical Africa and South America and are caused by parasitic protozoa. Human African trypanosomiasis (or sleeping sickness) is caused by two subspecies of Trypanosoma brucei and is transmitted by the bite of the bloodsucking tsetse fly. Chagas disease occurs in Latin America and is caused by Trypanosoma cruzi . This parasite is transmitted by triatomine bugs, which acquire infection by feeding on infected blood, but pass the parasites on to the next host via their infected faeces. The human trypanosomiases are zoonoses and a range of wild and domestic mammals can act as reservoir hosts for the parasites. There are no vaccines for these diseases and control relies on drug treatment and limiting opportunities for transmission. Key Concepts Human African trypanosomiasis and Chagas disease are both caused by insect‐borne, parasitic trypanosomes, but the diseases and the parasite life cycles are completely different. Control of the trypanosomiases relies on treatment of human patients and reduction of transmission, largely achieved through killing the insect vectors. The human trypanosomiases are zoonotic diseases and a range of wild and domestic mammals act as reservoir hosts for the parasites. Vector‐borne diseases with animal reservoirs have complex epidemiology and are difficult to control. Elimination of Human African trypanosomiasis as a public health problem in sub‐Saharan Africa seems likely if current treatment, surveillance and tsetse control measures are maintained. Animal reservoir hosts are more important in maintaining Human African trypanosomiasis in East Africa than West and Central Africa. Eradication of Chagas disease is thwarted by the longevity of infection in humans, circulation of the parasite in a wide range of animal reservoir hosts and transmission by routes other than the insect vector.