A case report of Clinostomum species infection of farmed Oreochromis niloticus in Kirinyaga County, Kenya
DOI:
https://doi.org/10.65869/sar.v5.i1.121Keywords:
Clinostomum sp., Histopathology , Infection , Metacercariae , Nile tilapiaAbstract
A farm study was undertaken at a commercial farm in Sagana town, Kirinyaga County, Kenya, whereit was discovered that Oreochromis niloticus in earthen ponds had massive digenean fluke cysts on the skin. In the farm large numbers of piscivorous birds were seen foraging in the fish ponds while snail shells were collected from the same ponds. Twenty fish from four ponds were collected and transported to Department of Veterinary Pathology, Microbiology and Parasitology (DVPMP), University of Nairobi (UoN) for necropsy, parasite identification and histopathology examination. Tissues were sectioned, routinely processed, stained with haematoxylin and eosin, examined and photographed. Piscivorous birds included the grey heron, kingfisher, great egret, little egret, African sacred ibis and hamerkop while snail shells belong to the family Lymnaeidae. On gross examination, multiple yellow to brown cysts were distinctly visible embedded in the skin. The causative agent of yellow grub disease was identified as Clinostomum sp. metacercariae which had a prevalence of 100% and a mean intensity of 40.1. Histopathology revealed metacercarial sections in the skin which were associated with pressure atrophy, capsule formation and intensive inflammation characterized by mononuclearcellular infiltration. Immune cells included macrophages, eosinophils, lymphocytes, fibroblasts and heterophils. Clinostomum sp. has both economic and public health importance as fish are rejected in the market due to the yellow grubs and it is a potential zoonosis causing laryngopharyngitis in humans. The high prevalence ofClinostomumsp. shows their potential impact on both fish and human health, emphasizing the need for continued monitoring and public education of fish consumers in the county.References
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