Ecological aspects of South American trypanosomiasis: III - local dispersion of triatomids, with special reference to Triatoma sordida

Abstract

Investigations on triatomids behaviour in the counties Guaira and Sertãozinho of São Paulo State, Brazil, are presented. Precipitin tests showed differents blood meals in Triatoma sordida, and mainly from avian source in Rhodnius neglectus. Nevertheless it was probably due to opportunities and not to any hematofagous preference on birds or mammals. Investigation at artificial ecotopes, represented by houses and outbuildings, showed common invasion of these dwellings by Triatoma sordida and, in a very scarce manner, by Rhodnius neglectus. This leads at the conclusion that the first bug are moving to search more stable ecotopes, represented by human dwellings, because the dry trees and fences are instable ones, where the blood sources are much more scarce. Beside this, passive transportation was demonstrated by founding nymphs and adults of T. sordida in dry woods piles, and first nymphs, between feathers of sparrows (Passer domesticus). Instalations of artificial chickenhouses were made, and only a positive result was obtained with Rhodnius neglectus. The conclusion was that distance play an important role concerning this bug. Nevertheless, the atraction of the human dwellings it seems to be more efficient for T. sordida and so, the domestic animal shelters will become concentration places for this bug. So a following increase of indoor density of T. sordida is expected.