andParasites (Eimeriidae, Apicomplexa) of Passeriform Birds in Europe: Infection Rates, Phylogeny, and Pathogenicity.

Abstract

Wild birds are common hosts to numerous intracellular parasites such as single-celled eukaryotes of the family Eimeriidae (order Eucoccidiorida, phylum Apicomplexa). We investigated the infection rates, phylogeny, and pathogenicity ofandparasites in wild and captive passerine birds. Blood and tissue samples of 815 wild and 15 deceased captive birds from Europe were tested using polymerase chain reaction and partial sequencing of the mitochondrialandand the nuclearrRNA gene. The infection rate forin wild birds was 10.7% compared to 5.8% for. Chromogenic in situ hybridization with probes targeting the parasites'rRNA was employed to identify the parasites' presence in multiple organs, and hematoxylin-eosin staining was performed to visualize the parasite stages and assess associated lesions.parasites were mainly identified in the intestine, spleen, and liver. Extraintestinal tissue stages ofwere accompanied by predominantly lymphohistiocytic inflammation of varying severity.was most frequently detected in the spleen, lung, and brain; however, infected birds presented only a low parasite burden without associated pathological changes. These findings contribute to our understanding ofandparasites in wild birds.