Prevalence of Coccidian parasites (Phylum Apicomplexa) in understory birds from the Atlantic Forest

Coccidia are among the most representative endoparasites in birds. They live in the gastrointestinal tract and extract nutrients that are essential for the host’s survival, leading to death when the infection is severe. This study aims to describe the prevalence of coccidians in understory birds of the Atlantic Forest and to test whether there exists a relationship between these parasites and host body mass. We conducted the study in ten sample units with different altitudes at Reserva Natural Guaricica (Paraná, Brazil). We captured 45 birds of 18 species and, from each individual, we measured body mass (m) and tarsal length (t) and we collected fecal samples. We prepared these samples following the sugar fluctuation protocol, preparing a slide for each bird. We found coccidia oocysts on 10 slides, totalizing a prevalence of 22%. Turdus albicollis exhibited the highest prevalence of infection (50%), followed by Schiffornis virescens and Xiphorhynchus fuscus (33.3%, each) and Conopophaga melanops (25%). We did not find a relationship between mass index (m/t) and incidence of oocysts in T. albicollis (t=-0.48, df=10, p=0.64), the most abundant species. This absence of a negative effect of endoparasites on T. albicollis may indicate that the degree of infection in these birds is not severe enough to affect their body condition (measured as body mass). Future studies may clarify whether there is a relationship between coccidia infection and other host’s characteristics.