Trypanosomiasis

Trypanosomiasis is a disease caused by protozoan parasites of the genus Trypanosoma. In humans, two major forms are recognized: African trypanosomiasis (sleeping sickness), caused by Trypanosoma brucei subspecies and transmitted by tsetse flies; and American trypanosomiasis (Chagas disease), caused by Trypanosoma cruzi and transmitted by triatomine bugs.

Transmission and life cycle: The parasites alternate between insect vectors and mammalian hosts. T. brucei is transmitted by the tsetse fly, with infection spreading during a bite. T. cruzi is deposited in bug feces and enters through mucous membranes or broken skin; other routes include congenital transmission, blood transfusion, organ donation, and ingestion of contaminated food.

Clinical features: African sleeping sickness has an initial hemolymphatic stage with fever, fatigue, lymphadenopathy, and sometimes a chancre, followed by a late neurological stage with sleep disturbances, cognitive problems, and motor symptoms. Chagas disease may be acute and mild, but chronic infection can cause cardiomyopathy and digestive system megasyndromes such as megacolon or megaesophagus.

Diagnosis and treatment: Diagnosis relies on detection of parasites in blood, lymph node aspirates, or tissue, plus serology or molecular tests. Cerebrospinal fluid analysis helps stage African disease. Treatments are species- and stage-specific: African sleeping sickness may be treated with pentamidine or suramin in early disease and with eflornithine or nifurtimox–eflornithine in CNS disease; melarsoprol is used in some settings. Chagas disease is treated with benznidazole or nifurtimox, most effective in acute infection and in children.

Prevention and public health: Control focuses on vector management, housing improvements, insecticide-treated materials, and screening of blood and organ donors. Surveillance and regional elimination efforts operate in parts of Africa and the Americas to reduce transmission and disease burden.