a sensitive and specific pcr based method for identification of cryptosporidium sp. using new primers from 18s ribosomal rna

background: the main goal of the present study was to develop a new sensitive and specific pcr based method for identification of cryptosporidium sp. using novel primers from 18s ribosomal rna. cryptosporidi­osis in high-risk host groups particularly in neonates and immuno-compromised individuals may result in death. to the best of our knowledge this is the first study regarding develop a new pcr based method to diagnose the cryptosporidiosis in iran. methods: a total of 850 human fecal samples from patients clinically suspected to cryptosporidiosis and 100 healthy and diarrheic cattle stool specimens were collected. the simplified formol-ether concentration method was carried out for all samples. they were then examined microscopically by modified ziehl-neel­sen staining method. total dna was extracted by qia amp dna stool mini kit was carried out by using designed prim­ers. results: twenty nine cases of cryptosporidiosis infection in human and 30 samples from cattle microscopi­cally were posi­tive. the described primary and nested pcr method could detect all cryptospori­dium positive samples from human and cattle. regards to suspected negative samples in pri­mary pcr examination, the nested pcr could ap­prove two more positive results. furthermore, nested pcr analysis was able to detect one more case which was nega­tive in both microscopically examination and primary pcr. specificity of the test was 100%. sensitivity of nested pcr in comparison to our gold standard; microscopy after ridley concentration modified ziehl-neelsen, was 100 %. conclusion: our developed pcr based method by using new primers devised from 18s ribosomal rna revealed the ability for identification of the cryptosporidium species such as c. parvum and c. huminis with high specificity and sensitivity.