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Title: INTESTINAL COCCIDIOSIS IN BLUEGILL, LEPOMIS MACROCHIRUS

Author
item Pasnik, David
item SMITH, STEPHEN - VMRCVM VPI&SU
item LINDSAY, DAVID - VMRCVM VPI&SU

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/11/2005
Publication Date: 8/1/2005
Citation: Pasnik, D.J., Smith, S.A., Lindsay, D.S. 2005. Intestinal coccidiosis in bluegill, lepomis macrochirus. Journal of Parasitology. vol 91 no 4 pp. 967-970.

Interpretive Summary: Coccidiosis is a significant disease in mammals but is often overlooked in fish because pathologic effects in fish are commonly limited. Clinical signs of intestinal coccidiosis in fish include general ill-thrift, lethargy, and emaciation. Though pathologic effects are generally non-fatal themselves, clinical coccidiosis can contribute to morbidity and mortality in an affected population. 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. This is the first known report of coccidiosis in bluegill, and our findings indicate that intestinal coccidiosis may pose a significant health problem in young bluegill. Furthermore, coccidiosis should be considered among primary differentials for young fish populations suffering chronic mortalities.

Technical Abstract: 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.