Morphological and histopathological description of Calyptospora sp. parasitism in Cichla monoculus Spix, 1929 (Osteichthyes, Cichlidae) from the lake region of Pracuúba-Amapá, Brazil.

The tucunaré (Cichla sp.) is an Amazonian fish that is heavily commercialized in the state of Amapá, and it can be infected by a variety of parasites, including coccidia of the genus Calyptospora, which are identified at the genus level by analyzing the structures that comprise its morphology. This study aimed to describe the morphology and histopathology of Calyptospora sp. parasitism in Cichla monoculus Spix, 1929 in the Municipality of Pracuúba, Amapá, Brazil. Nine specimens were acquired from the Lake Sacaizal by artisanal fishermen and transported in isothermal boxes to the Integrated Morpho-molecular and Technologies Laboratory (LIMT) of the Federal Rural University of the Amazon in Belém, Pará, where they were necropsied. Fragments of the liver were removed to visualize cysts using light microscopy and processed for scanning electron microscopy and histology analyses. The analysis revealed that 66.6% of the fish examined had clusters of oocysts in the hepatic region, resulting in the formation of melanomacrophagic centers. The oocysts were sphere-like, with a diameter of 21 µm. They contained four pyriform sporocysts, 8.7 µm long and 4.9 µm wide, with sporopods in the posterior region.