Ecological aspects of South American trypanosomiasis: XVIII - development and annual cycles of Triatoma infestans, T. sordida and Rhodnius neglectus colonies in artificial ecotopes in the peri and extradomiciliar environment

Abstract

Spontaneous colonies of Triatoma infestans, T. sordida and Rhodnius neglectus developed in experimental fowlhouses were observed for the conditions under which they developed, their variations, permanence, annual cycles and survival. Of nine of these colonies three were mixed, one of them with T. infestans and T. sordida and two with T. sordida and R. neglectus. For all the triatomine species the colonies' development showed a cyclic rhythm with an increase of the production of adults in the first semester of the year. For T. sordida this production was particularly high in the first three or four months of the year, followed by a similar pattern of females findings in the dwellings. An active dispersal capacity in T. infestans was demonstrated by the adults findings in the ecotopes surrounding dwellings. This cyclic dynamic of the colonies permits identification of the "infestant" period for the "susceptible" domiciliary environment represented by the cleaned dwellings. The reinfestation risk from extradomiciliary T. sordida and R. neglectus occurs at this time. At the same time, if there are previously developed T. infestans colonies in this environment, they may be dispersed to other new dwellings. The information will be of use in epidemiological surveillance.