Blood parasites in passerine birds from the Brazilian Atlantic Forest

parasites may lead bird species to extinction, affect host temporal and spatial population dynamics, alter community structure and alter individuals’ social status. we evaluated blood parasite prevalence and intensity according to bird families and species, among 925 birds that were caught in 2000 and 2001, in the atlantic forest in the state of minas gerais, brazil. we applied giemsa staining to thin blood smears, to detect blood parasites. the birds (n = 15.8%) in 11 families, were infected by at least one parasite genus, especially muscicapidae (28.3%) and conopophagidae (25%). among the 146 infected birds, plasmodium was detected in all bird families and had the highest prevalence (54.8%). trypanosoma, haemoproteus and microfilaria had lower prevalence rates (23.3, 23.3 and 2.1%, respectively). birds caught during the rainy season were more infected than birds caught during the dry season. the overall low prevalence of blood parasites in birds is similar to the patterns found elsewhere in the neotropical region.