Fibrosarcoma in Pond-Cultured African Catfish (Clarias gariepinus)

Abstract

There is dearth of information in literature about the occurrence and pathology of fibrosarcoma in the African catfish. However, there are a few reports of fibrosarcoma in other fish species and most have been virally associated. Twelve moribund and dead African catfishes with ages ranging from two months to one year were collected from a fish farm during two different disease outbreaks over a two year period. At necropsy, tumours were observed on the head, dorsum, lateral to the dorsal fin, flanks, caudal penduncle, tail, in the musculature, ovaries, abdominal wall, and abdominal fat. Histologically, the tumour was composed of atypical spindle cells (fibroblasts) and collagenous stroma. The neoplastic fibroblasts also invaded surrounding tissue (skeletal muscle and fat). Transmission electron microscopy of the neoplasm revealed numerous retrovirus-like particles within the cytoplasm of degenerate and necrotic fibroblasts. On the basis of these findings, the tumour was classified as a fibrosarcoma. To our knowledge, this could constitute the first report of fibrosarcoma associated with a virus in the African catfish. Further study will be required to isolate and characterise this virus as well as investigating the possible role of this virus in the pathogenesis of this neoplasm.

Keywords: African catfish, Fibrosarcoma, Virus.