In parts of tropical Africa tsetse flies can carry parasites called Trypanosoma that causes sleeping sickness. Best protection against this disease is avoiding the tsetse fly bites (see below). The risk of transmission to travelers is quite low, but if you plan to visit wildlife parks and remote rural areas of tropical Africa, you should take precautions.

   Background information

Transmission and pathogeneSleeping sickness (or Trypanosomiasis) is a systemic disease caused by the parasite Trypanosoma brucei. It is transmitted by the bite of the tsetse fly, a gray-brown insect about twice the size of a housefly. Only a small proportion of the tsetse flies carries the parasite. There are two forms of African sleeping sickness, each caused by a different parasite : Trypanosoma brucei gambiense, which causes a chronic infection lasting years and affecting countries of western and central Africa Trypanosoma brucei rhodesiense, which causes acute illness lasting several weeks in countries of eastern and southern Africa. OccurrenceAfrican trypanosomiasis is confined to tropical Africa between 15 degrees North and 20 degrees South latitude. See map . Risk for travelers and protective measuresTsetse flies feed on the blood of animals and humans and inhabit rural areas only, living in the vegetation along watercourse and lakes, forest edges and savannah. Although infection of international travelers is rare, cases have occurred and persons visiting game parks and remote areas should take precautions. Travelers to urban areas are not at risk.

Tsetse flies are attracted to moving vehicles, to perfume and aftershave and dark, contrasting colors. They are not affected by insect repellents and can bite through lightweight clothing. Areas of heavy infestation tend to be sporadically distributed and are usually well known to local inhabitants. Avoidance of such areas is the best means of protection. Travelers at risk should wear clothing of wrist and ankle length that is made of medium-weight fabric in neutral colors that blend with the background environment. SymptomsThe first sign of infection is swelling or a rash at the site of the bite, about one week later. This is followed by fever within two to three weeks, other clinical signs are weakness, headache, joint pains and pruritus (itching). In the advanced stage of the disease the parasite invades the central nervous system leading to meningoencephalitis with behavioral changes, loss of concentration and interest, lethargy and coma.

East African Trypanosomiasis (caused by T.b.rhodesiense) is usually more acute clinically than the West African form of the disease (caused by T.b.gambiense), and central nervous system involvement occurs earlier. VaccineNo vaccine is available. TreatmentWithout appropriate treatment both forms of sleeping sickness are fatal, so Trypanosoma brucei infection should be treated as early as possible. Drug of choice is Suramine (Germanin®), which kills the parasites quite effective in early stages. In advanced disease, when the central nervous system is affected, the disease is treated with arsene preparations such as melarsoprole.

For decades, no new substances have been invented for the therapy of trypanosomiasis. Apparently, the pharmaceutical industry does not bother too much about this poor man's disease.