Developmental stages of Sarcocystis spp. in wild birds from Southeastern Brazil, with a review of Accipitriformes-associated species

The genus Sarcocystis comprises apicomplexan parasites associated with clinical manifestations, including reproductive and neurological disorders, in a wide range of domestic and wild animals. Infections by Sarcocystis spp. have been reported in birds on all continents except Antarctica. In this context, the present study reports two cases in which Sarcocystis spp. were identified at different developmental stages, endogenous and exogenous, in wild birds captured in Southeastern Brazil. Oocysts and sporocysts were detected in the feces of a roadside hawk Rupornis magnirostris, captured on Marambaia Island, Rio de Janeiro State, Brazil. In addition, bradyzoite cysts were observed in the muscle tissue of a rufous-bellied thrush Turdus rufiventris, captured in Itatiaia National Park. Accordingly, this study provides comments on the parasitic dynamics of Sarcocystis spp. in a wild environment and discusses the potential species involved in these host-parasite associations. For Sarcocystis sp. detected in the rufous-bellied thrush, based on evidence from previous studies, we strongly suggest that this species is Sarcocystis falcatula. In contrast, for Sarcocystis sp. detected from the roadside hawk, no specific species assignment can be made, as data on hawks acting as definitive hosts of Sarcocystis spp. in South America remain scarce. Although S. falcatula may involve Accipitriformes in its life cycle, members of this order are considered intermediate rather than definitive hosts for this species. Therefore, we present herein a survey of Sarcocystis spp. that involve Accipitriformes in their life cycles, including comparative data on sporocyst measurements for each species.