molecular epidemiology of cryptosporidiosis in iranian children, tehran, iran

background: cryptosporidium is a worldwide protozoan parasite and one of the most common causes of infection and diarrhea in humans and cattle. the aim of the present study was determina­tion of subtypes of cryptosporidium among children with diarrhea in tehran by se­quence analysis of the highly polymorphic 60-kda glycoprotein ( gp60 ) gene. methods: fecal samples were collected from 794 diarrheic children. initial identification of crypto­spo­ridium was carried out on stool samples by ziehl-neelsen acid-fast staining method. dna was extracted from positive microscopically samples and cryptosporidium genotypes and subtypes were determined, accordingly. results: out of 794 collected samples, 19 (2.40 %) were positive for cryptosporidium oocysts. sequences analysis of gp60 gene showed that 17 (89.47 %) of the positive isolates were crypto­spori­dium parvum and 2 (10.52 %) were c. hominis . all subtypes of c. parvum isolates belonged to allele families iia (6/17) and iid (11/17). the most common allele in all 17 isolates belonged to iid a20g1a (41.18%). a22g1 (if) subtype was detected in two c. hominis isolates of the chil­dren. conclusion: the predominancy of c. parvum species (specially, iid a20g1a sub­type) in current study underlines the importance of zoonotic cryptosporidium transmission in iran.