Intestinal coccidiosis in bluegill, Lepomis macrochirus

Developmental stages of a coccidial parasite were observed in young-of-year bluegill (Lepomis macrochirus) from an impoundment lake in Norfolk County, Virginia. The fish were anorexic and lethargic. Necropsy examination revealed emaciated bluegill with little or no abdominal fat and no food in the stomach or intestines. Coccidia were present in the posterior intestine in moderately large numbers. Few sporulated oocysts were present, and identification to genus was not possible. Epithelial cell destruction, sloughing of the intestinal mucosa, and hemorrhage were associated with the developing coccidial parasites. Coccidia were not observed within other organ systems. No pathogenic bacteria were isolated from the fish tissues. Our findings indicate that intestinal coccidiosis may pose a significant health problem in young bluegill.