detection and enumeration of cryptosporidium oocysts in environmental water samples by real-time pcr assay

Introduction: the protozoan parasite, cryptosporidium spp., widely spreads in both raw and drinking waters. it is the causative agents of waterborne diarrhea and gastroenteritis in the world. in the present study, a molecular assay was used for the detection and quantification of cryptosporidium oocysts in environmental water samples. materials and methods: thirty surface water samples were collected from rasht city rivers and lagoons during 2009-2010. the samples were analysed for cryptosporidium oocysts using real time pcr method. samples were filtrated through a 1.2μm pore size cellulose nitrate membrane filter and then purified and quantified by real-time pcr technique. results: cryptosporidium oocysts were found in 19 of 30 the samples. oocyst concentration was ranging from 0.007 to 27 oocysts per liter of the examined waters. conclusion: the present study showed that the investigated water supplies were contaminated by cryptosporidium oocyst. this study indicated that in this level of oocysts there is a potential risk of waterborne cryptosporidiosis due to direct or indirect consumption of these waters by humans and animals. real-time pcr is a technique that provides high sensitivity for detection quantitative purposes.