Plasmodium and Leucocytozoon (Sporozoa: Haemosporida) of Wild Birds in Bulgaria

Three species of parasites of the genus Plasmodium (P. relictum, P. vaughani, P. polare) and 6 species of the genus Leucocytozoon (L. fringillinarum, L. majoris, L. dubreuili, L. eurystomi, L. danilewskyi, L. bennetti) were found in the blood of 1332 wild birds of 95 species (mostly passerines), collected in the period 1997-2001. Data on the morphology, size, hosts, prevalence and infection intensity of the observed parasites are given. The total prevalence of the birds infected with Plasmodium was 6.2%. Plasmodium was observed in blood smears of 82 birds (26 species, all passerines). The highest prevalence of Plasmodium was found in the family Fringillidae: 18.5% (n=65). A high rate was also observed in Passeridae: 18.3% (n=71), Turdidae: 11.2% (n=98) and Paridae: 10.3% (n=68). The lowest prevalence was diagnosed in Hirundinidae: 2.5% (n=81). Plasmodium was found from March until October with no significant differences in the monthly values of the total prevalence. Resident birds were more often infected (13.2%, n=287) than locally nesting migratory birds (3.8%, n=213). Spring migrants and fall migrants were infected at almost the same rate of 4.2% (n=241) and 4.7% (n=529) respectively. Most infections were of low intensity (less than 1 parasite per 100 microscope fields at magnification 2000x). Leucocytozoon was found in 17 wild birds from 9 species (n=1332). The total prevalence of Leucocytozoon was 1.3%.