Hepatic coccidiosis in Bagre Bagre (Linnaeus, 1766) from the Brazilian Amazon Region Caused by Calyptospora Matosi n. sp. (Apicomplexa: Eimeriidae).

Purpose: Coccidia (Coccidiasina) is a subclass of Apicomplexa, known to cause gastrointestinal diseases in animals. Although its importance is recognized, there are few taxonomic studies of coccidia in fish, especially in biomes with high diversity, such as the Brazilian Amazon. Therefore, the present study investigated infections by coccidian microparasites found in the hepatic region of the Coco sea catfish, Bagre bagre.

Methods: Parasitological analyses were performed on 50 specimens of B. bagre collected in Bragança and Curuça, in northern Brazil, between January and December 2021.

Results: Infections caused by coccidiosis were identified in 35 of these specimens, which were infected by parasites of the genus Calyptospora, including both sporulated and non-sporulated forms in the hepatic stroma of the hosts. The oocysts were spherical (mean diameter: 10.52 ± 0.29 μm) and contained four spheroid sporocysts (mean diameter: 4.22 ± 0.23 μm). A consensus sequence (1,320 bp) of the SSU rDNA gene from these parasites was compared with GenBank sequences of other species of the class Coccidiomorphea and the genetic distances indicated that they represented a new species.

Conclusion: The combination of the morphometric and phylogenetic evidence supports conclusively the existence of a new species of the genus Calyptospora, which is denominated Calyptospora matosi n. sp.