Protozoal Tropical Infections

© 2005 The Medicine Publishing Company Ltd 50 MEDICINE 33:8 Different species of the protozoan Trypanosoma are of similar appearance (Figure 1), and all are termed ‘kinetoplastids’ because they move using a flagellum that obtains energy from a mitochondrion called a plastid. However, trypanosomes also differ in many ways, including aspects of their molecular and cellular biology, their transmission, and the diseases that they cause.1 • Infection with T. brucei causes two forms of sleeping sickness in humans (Figure 2) – acute infection of the East African type, caused by T. b. rhodesiense, and a more chronic infection caused by T. b. gambiense (West African type). Both are fatal if untreated. • T. cruzi infection acquired in Central or South America progresses over many years to Chagas disease in up to 30% of patients. Sleeping sickness and Chagas disease are neglected, particularly because they are only rarely imported into Europe. Two brothers returning from an East African safari were recently diagnosed with African trypanosomiasis,2 but fewer than a dozen cases were diagnosed in Europe in the last 5 years. Chagas disease is even less common in Europe. Both can be transmitted through blood.