Prevalence, intensity and pathological lesions associated with contracaecum species infection in farmed and wild catfish in the upper Tana river basin, Kenya

Abstract

A total of 108 randomly selected farmed and wild Clarias gariepinus (catfish) obtained from the upper Tana river basin were examined for intestinal helminthes between July 2007 and April 2008. Over fifty nine point three per cent (59.3 % ) of the catfish had Contracaecum species larval worms in the abdominal and branchial cavities. The prevalence of the parasite in farmed fish was 18.5 %, wild catfish 40.7 % (p < 0.05), whereas adult catfish had a prevalence of 37.0 % while young had 22.2 % (p < 0.05). There was no significant difference in the Contracaecum spp. infection between males and female catfish (p > 0.05). Branchial cavity infection prevalence was 3.7 % while that of the abdominal cavity was 55.6 %. Farmed catfish mean load was 3.5 worms per fish, wild 185.1; female catfish had a mean load of 77.4 while males had 167.8, whereas adult catfish had a mean count of 161.2 while for the young fish was 69.7. The infection varied from mild to severe. There was significant differences in the mean worm load between the farmed and wild, the sexes and the age groups (P < 0.05). Gross lesions of peritoneal adhesions with at a mean prevalence of 58.3 % with microscopic lesions of severe infiltration of mononuclear and polymorphonuclear cells as well as fibroblasts into the mesenteries, gastro intestinal tract were also observed. This study reports the occurrence of Contracaecum spp. and associated pathology in catfish in Kenya for the first time.