New data on Eimeria dicentrarchi (Apicomplexa: Eimeriidae), a common parasite of farmed European sea bass (Dicentrarchus labrax) from the mid-eastern Adriatic.

This study extends the original description of Eimeria dicentrarchi Daoudi and Marquès, 1987, a common coccidian parasite of European sea bass from the mid-eastern Adriatic, by providing insights into the parasite’s site of infection, development and pathogenicity. E. dicentrarchi was found in various developmental stages in most segments, mainly anterior, of the digestive tract. In infected segments of the digestive tract, merogonic and gamogonic stages were located in the enterocyte cytoplasm, whereas sporogonic stages were situated in the epithelium and occasionally beneath it, in the lamina propria. Most oocysts in the lumen of the digestive tract were completely sporulated, indicating endogenous sporulation. E. dicentrarchi infection caused localised histopathological changes, restricted primarily to individual epithelial cells. Additionally, the results of our preliminary study suggest that oral administration of potentiated sulphonamide Trimetosul® (trimethoprimsulfadiazine) may be effective against E. dicentrarchi infection.