trypanosomiasis

African trypanosomiasis an often fatal disease of Africa caused by Trypanosoma gambiense or T. rhodesiense and involving the central nervous system. The parasites are transmitted to human beings from cattle or other animals by the bite of the tsetse fly. Usually the first symptom is inflammation at the site of the bite, appearing within 48 hours. Within several weeks the parasites invade the blood and lymph, and eventually they attack the central nervous system. Characteristic symptoms include intermittent fever, rapid heartbeat, and enlargement of the lymph nodes and spleen. In the advanced stage of the disease there are personality changes, apathy, sleepiness, disturbances of speech and gait, and severe emaciation.



Pharmacologic treatment should begin as soon as possible and is based on lab results and patient symptoms. suramin, pentamidine isethionate, and melarsoprol are the most common medications used. Pentamidine isethionate or suramin may be injected to remove parasites from the blood or lymph nodes before onset of disease, but the most effective preventive measure is eradication of the tsetse fly.

American trypanosomiasis (South American trypanosomiasis) a form found from the southern United States south into South America, caused by Trypanosoma cruzi; it is transmitted to humans from wild animals by means of the feces of a blood-sucking bug. The parasites multiply around the points of entry before entering the blood and eventually attacking the heart, brain, and other tissues. Called also Chagas' disease.



The acute form often attacks children. Early symptoms include swelling of the eyelids and the development of a hard, red, painful nodule on the skin. Enlargement of the lymph nodes, liver, and spleen occurs, along with inflammation of the heart muscle, psychic changes, and general debility. In adults the chronic form often resembles heart disease.

The control strategy suggested by the World Health Organization is to interrupt transmission of the disease by the vectors and to systematically screen blood donors. Preventive measures, such as the wearing of protective clothing and the use of insecticides, are of primary importance. Medication with antiprotozoal agents is usually effective when administered during the acute stage of infection.