RESUMO
Since Cryptosporidium is a worldwide distributed protozoan parasite and is considered as one of the most common causes of infection and diarrhea in humans with autoimmune deficiency, as well as in young live stock, molecular epidemiologic studies of cryptosporidiasis will be helpful for underlying transmission and molecular pathogenesis of Cryptosporidium in humans. The aim of the present study was to determine the species and genotypes of Cryptosporidium among children with diarrhea in Tehran and Qazvin provinces by PCRRFLP using the three polymorphic regions of SSU-rRNA, COWP and TRAP-C2 genes. 1263 stool samples were collected from the children less than 12 years with diarrhea who referred to Pediatrics Medical Centers in Gazvin and Tehran Provinces, Iran, during 2005-2007. After determination of the presence of Cryptosporidium oocytes by ZiehlNeelsen acid, fast staining genomic DNA was extracted. Nested PCR-RFLP was performed by -rRNA, COWP and TRAP-C2 genes. Results of microscopically positive samples showed that the overall prevalence of infection in children was 31 [2.5%]. Results of nested PCR amplification showed that of 31 isolates of children, all of three targeted gene were successfully amplified. Our results indicated that the zoonotic transmission is the main mode of infection in Iran and indicates that direct or indirect contact with animals, especially calf, is possibly the main route of human infection