Fonte alimentar e potencial vetorial de Triatoma vitticeps (Stal, 1859) com relação à doença de Chagas humana no estado do Espírito Santo, Brasil (Hemiptera, Reduviidae)

Abstract

In parallel with several other epidemiologic and entomologic data of 19 Municipalities of Espirito Santo State, Brazil, the feeding pattern of 222 Triatoma vitticeps is studied through precipitin tests. Very high levels of natural infection with Trypanosoma cruzi are observed in adult insects, in contrast with the absence of minimum degrees of infection among nymphs and human individuals. The precipitin tests shows the contact of the insects with multiple blood sources, chiefly human and birds, followed by rodents and marsupials. The data suggest that T. vitticeps in spite of being highly anthrophilic, become infected by T. cruzi in sylvatic ambient and occasionally invade houses. The species doesn''t seem to be - at least until now - a good vector in the domestic cycle of Chagas'' disease. Several factors seem to be involved in this conclusion, mainly the low density of the insect in the houses, its hardness to colonize them, its slowness concerning to suction and defecation and possibly its low susceptibility to different T. cruzi strains.