Abstract: 　Objective To develop a pair of diagnostic PCR primers for Cryptosporidium parvum . Methods A species-specific gene fragment of C.parvum was obtained through RAPD analysis. After the fragment was isolated,purified,cloned and sequenced,a pair of primers FF was designed and synthesised based on the sequence. With the primers, the anticipated fragment in size of 603 bp was amplified by PCR from 2 American strains and 4 Chinese strains of C.parvum . The samples of 35 rabbits feces and 55 human feces were detected by PCR with primers FF and 021,the latter was a species-specific diagnostic primer reported by Morgan. Results All six strains amplified by the primers FF showed same detection rate with 021. Sensitivity test indicated that DNA of 1 oocyst per gram of feces could be detected by the PCR. Conclusion The primers FF showed high specificity and sensitivity, and can be used for diagnosing Cryptosporidium parvum infection.

Key words: Cryptosporidium parvum, diagnosis, primer