Trichosomoides crassicauda infection in wistar rats

Laboratory animals, including rats, play an important role in biomedical research and advances. the human care and management of these animals is an ongoing concern. since, trichosomoides infections in rat colonies can interfere with research protocols it is important to know rate of infection and pathology of the infection in the animals used in experimental studies. 275 rats were eviscerated and urinary bladders were collected. the numbers of collected nematodes from each of the urinary bladders were counted under a stereomicroscope and identified on the basis of morphological criteria. tissue sections were collected and processed routinely for histopathological studies. out of 275 urinary bladder of adult laboratory wistar rats examined, 156 (56.72%) were infected with the nematode, trichosomoides crassicauda. there was significant difference (p < 0.05) in infection in female and male rats, with rate of 47.73% and 80.26%, respectively. the number of nematodes collected from each infected rats ranged from one to fourteen with an average of three nematodes per animal. histopathological evaluation revealed multiple parasites with variable degree of lesions in transitional epithelium of urinary bladder. parasites were lying upon the epithelium or located in chambers between epithelial cells. also immature and embryonated eggs were seen in female worms. other lesions were as follow: hyperplasia of epithelium, erosions, ulcers and eosinophilic cystitis. this study reports the data on the presence of helminth parasites in laboratory rat colonies, and suggests paying attention on controlling the sanitary conditions of animal houses.