Current spread of Triatoma infestans at the expense of Triatoma sordida in Bolivia

Abstract

Triatoma infestans is the most widespread synanthropic species of Triatominae and the most important vector of Chagas disease in South America. The progressive geographical expansion of this species from its silvatic focus of origin in the Cochabamba valley of Bolivia (JP Dujardin et al. 1987 J Med Entomol 24: 40-45) was probably associated with human migration into the continent (CJ Schofield 1988 Biosystematics of haematophagous insects, p. 285-312. MW Service Oxford). Triatoma sordida, a species associated with silvatic and peridomestic habitats, is currently found in houses in some rural areas of Bolivia, particularly in La Paz and Santa Cruz departments (E De Muynck 1977 Bol Inform CENETROP 3: 41-51, F Noireau et al. 1995 J Med Entomol 32: 594-598). The analysis of the present distribution of T. sordida in Bolivia, in comparison to 20 years ago data, gives a clear indication of the reduction of the area within which this species is found in houses and its substitution by T. infestans, the most important vector of Chagas disease in this country.