DAO 94:125-134 (2011)  -  DOI: https://doi.org/10.3354/dao02322

Histochemical and ultrastructural analysis of pathology and cell responses in gills of channel ­catfish affected with proliferative gill disease

J. Lovy1,*, A. E. Goodwin2, D. J. Speare3, D. W. Wadowska4, G. M. Wright5

1Fisheries and Oceans Canada, Pacific Biological Station, Aquatic Animal Health Unit, 3190 Hammond Bay Road, Nanaimo, British Columbia V9T 6N7, Canada
2University of Arkansas at Pine Bluff, Aquaculture/Fisheries Center, Pine Bluff, Arkansas 71601, USA
3Department of Pathology and Microbiology, 4Department of Graduate Studies and Research, and 5Department of Biomedical Sciences, Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, Prince Edward Island C1A 4P3, Canada

ABSTRACT: Pond-reared channel catfish Ictalurus punctatus with proliferative gill disease (PGD), caused by the myxozoan parasite Henneguya spp., were examined with light and transmission electron microscopy to better characterize the inflammatory response during infection. The early stages of disease are characterized by the destruction of collagen in the matrix of the gill filament cartilage causing weakness and breaks within the gill filaments. These early lesions lacked a notable inflammatory response around the disrupted cartilage, a chondrocyte response was not apparent, and the parasite was not present, suggesting that the cartilage breaks occur prior to inflammation and arrival of the parasite in the gill. In later lesions, a significant inflammatory response was generated in areas of disrupted cartilage, and the inflammatory infiltrate was composed of a mixed population of granulocytes including neutrophils and cells that resembled eosinophils. The majority of eosinophil-like cells demonstrated evidence of degranulation. Trophozoites of Henneguya spp. were surrounded by a uniform population of cells believed to be neutrophils. The granulocytes were infiltrated within the dense collagen layer of the gill filament cartilage and often appeared within chondrocyte lacunae in place of the chondrocyte. The gill lamellae adjacent to the lesions were fused and contained an inflammatory infiltrate containing granulocytes and cells with pericentriolar granules that resembled previous descriptions of Langerhans-like cells. These cells were abundant within damaged lamellar epithelium, but were only rarely found within the gill filament. Lesions that appeared to be recovering lacked the dense collagenous layer around the cartilage and contained hyperplastic and hypertrophic chondrocytes that formed a callus. Other chondrocytes in the lesions had ultrastructural features indicative of cell death.


KEY WORDS: Channel catfish · Proliferative gill disease · Inflammation · Henneguya · Collagen · Pathology · Ultrastructure


Full text in pdf format 
Cite this article as: Lovy J, Goodwin AE, Speare DJ, Wadowska DW, Wright GM (2011) Histochemical and ultrastructural analysis of pathology and cell responses in gills of channel ­catfish affected with proliferative gill disease. Dis Aquat Org 94:125-134. https://doi.org/10.3354/dao02322

Export citation
Mail this link - Contents Mailing Lists - RSS
- -