African Trypanosomiasis

What is African Trypanosomiasis?

African Trypanosomiasis or African Sleeping Sickness is a disease caused by the parasite Trypanosoma brucei (T. b.) which is transmitted by the bite of tsetse fly. There are two types of trypanosomiasis in Africa: East African type is caused by T. b. rhodesiense and prevalent in eastern and southern Africa; while West African type is caused by T. b. gambiense and prevalent in western and central Africa. The disease is widespread in sub-Saharan countries, with the incidence rate as high as 80% in epidemic areas. The disease can also infect cattle, causing high death rate, thus aggravating the poverty in the sub-Saharan countries. In 2004, large outbreaks were reported in northern Angola and Democratic Republic of the Congo.

Signs and symptoms are initially nonspecific like fever, skin rash, edema and lymph node enlargement. The infection can progress to inflammation of the brain and meninges. East African trypanosomiasis is more acute with earlier brain involvement than in the West African form of the disease. In the late stage the disease is characterized by slowly progressive neurological symptoms with increasing sleepiness eventually leading to a coma and death (hence the name of sleeping sickness)

How does it spread?

African trypanosomiasis is transmitted by bite of tsetse fly. The parasite then invades the blood and lymphatic system and multiples there. Later it migrates to the brain and cause inflammation and nervous system symptoms. The incubation period varies with different types of parasite, varying from 2 weeks to several years.

Tsetse flies are found in tropical Africa only and inhabit rural areas, living in the woodland and savannah and the dense vegetation along streams. Although infection of travellers is rare, the number of cases in travellers, primarily to East African game parks, has increased in recent years. Travellers to urban areas are not at risk.

How can you prevent it?

No vaccine is available to prevent this disease. Tsetse flies are not affected by insect repellents.

As tsetse flies can bite through lightweight clothing, the best means of protection is to avoid areas of heavy infestation. Travellers to affected areas should cover exposed parts of the body and avoid wearing the colour blue which attracts tsetse flies.

How is it treated?

Travellers who have been bitten by a tsetse fly and develop high fever should seek early medical attention. With appropriate medication, the infection is usually curable.