Coccidian Prevalence and Intensity in Free-Ranging and Rehabilitating Wild Raptors

Abstract

Coccidians infect the intestines and other organs in vertebrates, causing pathogenicity ranging from symptomatic infections to death. However, knowledge about coccidian infections is lacking for most free-living raptor species. Gathering basic information on coccidian infection would allow a better understanding of the basic ecology of raptors and would improve conservation actions. In this study, we assessed the prevalence and parasitic loads of coccidians in several free-ranging and rehabilitating wild raptor species in recovery centres in Spain and Belgium from 2015 to 2017. Faecal samples from 129 individuals of 17 different raptor species were collected. Coccidian oocysts were found in nine species. Significant differences were found in the prevalence of coccidians between the two countries, with higher rates in Belgium (45.0%) than in Spain (20.2%), as well as between age categories, with nestlings and juveniles showing a higher prevalence (30.5%) than adults (11.4%). Three different coccidian genera were identified. Caryospora spp. and Eimeria spp. were found in diurnal raptors and owls with medium/high loads (median ranging from 75-91344 ooc/g), while Isospora spp. was found only in Griffon Gyps fulvus and Egyptian Vultures Neophron percnopterus at low infection intensities (62-170 ooc/g). We present the first case of Isospora spp. in European vultures, although it is unclear if this is a true intestinal parasitisation or a pseudo-parasitisation with oocysts from livestock on which the vultures fed. Despite the limited sample size in our study, our results contribute to filling a gap in the knowledge of coccidian infections in wild birds.