Detection of Experimental Cryptosporidiosis in Neonatal Mice and Rats by Nested-PCR

Purpose: The purpose of this study is to model Cryptosporidiosis in laboratory animals. The parasites were inoculated into animalsand thenmultiplied. The process of proliferation was compared to controlCryptosporidiosis in humans. Materials and Methods: Twenty-five laboratory mice (4-7 days of age) and twenty-five laboratory rats (5 days of age) were assigned to the category I while the category II (control group) consisted oftwenty-fiverats and twenty-five mice. The two categories were infected with 5×105 Cryptosporidium parvum oocysts originated from a calf by using a 24-gauge & 20-gauge ball-point feeding needle. On 4-9 days of post inoculation the intestine, colon, and rectum were removed. Cryptosporidium infection was determined by detecting oocysts in intestinal homogenates by Staining and PCR method. Simple extraction and purification method was used by ficoll gradient centrifugation. Also, twenty laboratory rats (4-6 weeks of age) were intramuscularly injected with dexamethasone(Sigma, Chemical Co. UK) two times per week, and the last injection was given with 5×105 Cryptosporidium parvum oocyst on the same day as oral inoculation. The water was supplemented with tetracycline to avoiding secondary infections. Results: Two to four million purified oocysts with a maximum of 10 million were routinely obtained per mouse and rat. Also the day in which oocyst excretion is the highest was determined. The number of oocyst per neonatal mouse was (11±2)×105 on 9-12 days of post infection while similarly it was (10±1)×105 per neonatal rat. Conclusion: The evaluation of the cryptosporidiosis in immunocompromised animal models can help us to understand and control the Cryptosporidium infections.