A Nested-PCR Assay for Detection of Cryptosporidium parvum Oocysts in Water Samples

Cryptosporidiosis is a gastroenteric disease caused by the protozoan parasite cryptosporidium parvum. water–borne transmission of this organism has become more prevalent in recent years. current method for detection of c. parvum oocysts in water is immunofluoresence assay (ifa). the method is time consuming, laborious and particularly not–specific. it cannot determine the infectivity of detected oocysts. we have evaluated a nested- pcr assay for sensitive detection of c. parvum oocysts in water samples. water sample concentrates were spiked with cryptosporidium oocysts and after dna extraction and purification by qiaamp dna mini kit, detection was achieved by nested pcr amplification of a 200 bp region of hsp70 gene specific for c. parvum. the method could detect as few as one oocyst in seeded tap water samples. on the basis of these results, pcr could be a useful tool in the monitoring of water samples for the detection of cryptosporidium oocysts.