AWWA WQTC50361

Cryptosporidium parvum is a coccidian waterborne pathogen responsible for gastrointestinal illness in humans, particularly in immuno-compromised individuals. The classical method based on indirect immunofluorescence assay (IFA) routinely used for the detection of Cryptosporidium oocysts in water is time-consuming, inefficient, non-specific for C. parvum and unable to determine the viability of detected oocysts. In order to circumvent these limitations, three sensitive and rapid molecular assays were developed. Two of them could determine the presence/absence of Cryptosporidium and C. parvum in environmental water samples while the third targeted viable C. parvum oocysts. These molecular tests combined an ImmunoMagnetic Separation (IMS) step to capture oocysts directly from water concentrates with a specific amplification step by PCR or Reverse Transcription -PCR (RT-PCR). Both IMS-PCR assays were able to detect the presence of a single oocyst in water samples, thereby guaranteeing the absence of Cryptosporidium and C. parvum. The detection limit of the IMS-RT-PCR assay, which targeted heat shock-induced mRNA, was in the range of 10 viable oocysts. The two presence/absence IMS-PCR assays allow water samples to be rapidly screened (i.e., in seven hours) for Cryptosporidium/C. parvum. In the event of a positive result for C. parvum, the IMS-RT-PCR assay provides viability information concerning the detected oocysts, and accurately determines the risks posed to public health by waterborne Cryptosporidium. Includes 17 references, table, figure.

Product Details

Edition:

Vol. - No.

Published:

01/01/1999

File Size:

1 file , 300 KB