American trypanosomiasis (Chagas' disease) and the role of molecular epidemiology in guiding control strategies

Abstract

Chagas' disease is a parasitic infection that has far reaching consequences for public health and national economies in Latin America. The latest molecular typing methods may help in developing targeted, effective control programmes

Fig 1

Transmission cycles of Trypanosoma cruzi. (a) Enzootic transmission in the Amazon rainforest: no domestic colonies of triatomine bugs exist, but infrequent, sporadic cases of Chagas' disease may occur due to adult bugs flying to palm presses or houses, or when the triatomine species Rhodnius brethesi attacks workers sleeping in the forest to harvest piassaba palms. (b) An example of separate silvatic and domestic transmission cycles in Bahia state, Brazil: left, houses are infested by the triatomine bug Panstrongylus megistus; right, bromeliad epiphytes, refuges of the opossum (Didelphis albiventris), are infested by the triatomine bug Triatoma tibiamaculata. T cruzi II is found in the domestic cycle and T cruzi I in the silvatic cycle. (c) An example of overlapping silvatic and domestic transmission cycles in parts of Venezuela: the triatomine genus Rhodnius has several similar species; R prolixus may infest both houses and palms. Molecular analysis of triatomine vectors and T cruzi isolates shows where silvatic and domestic cycles are linked, which influences the design of control programmes (reproduced with permission from James Patterson)

Fig 2

Chagas' disease: clinical phases (reproduced with permission from James Patterson)