Coccídios em aves silvestres da ilha do Maranhão: uma ameaça à saúde animal e à biodiversidade? desvendando os riscos e buscando soluções

Abstract

Coccidiosis, caused by intracellular protozoa of the Eimeriidae family—primarily of the genera Eimeria and Isospora—has historically been underestimated within the context of Brazilian wild avifauna, despite representing a significant threat to animal health and biodiversity. This study presents the first systematic survey of coccidian occurrence in wild birds on Maranhão Island, an ecologically strategic region in northeastern Brazil characterized by coastal ecosystems and the presence of both resident and migratory bird species. A total of 136 fecal samples were collected between 2022 and 2024 during three seasonal expeditions (April/2022, September/2023, and April/2024), conducted preferably in the morning hours (6:00 to 11:00 a.m.), which correspond to the peak activity of target species. Each sample was divided into two aliquots: one underwent coproparasitological screening within 48 hours of collection, while the other was stored at −30 °C for subsequent DNA extraction and molecular analysis. Coproparasitological screening revealed that 5.15% (7/136) of the samples contained only coccidian oocysts, and 9.56% (13/136) showed concomitant presence of coccidian oocysts and helminth eggs, totaling a 14.70% (±4.94%) positivity rate. Among the 20 positive samples, 30% (6/20) were confirmed by PCR for protozoa of the genera Eimeria or Isospora. Two of these samples were subjected to molecular sequencing, with one identified to the genus level as Isospora spp., constituting the first molecular record of this genus in the avifauna of Maranhão Island. These findings underscore the importance of animal and environmental health surveillance in areas of ecological overlap between wild fauna and anthropogenic environments. Although coccidia do not pose a direct zoonotic risk, they may compromise biodiversity conservation and the health of domestic species, reinforcing the need for sustained monitoring strategies. The combination of originality, unprecedented regional scope, and methodological rigor provides scientific robustness and practical applicability to the study, highlighting the role of environmental education and public engagement in biodiversity conservation.