AWWA QTC98353

This study compared four methods for the assessment of viability and infectivity of Cryptosporidium parvum after UV inactivation. Seven seeded challenges were examined by vital dye staining with DAPI and PI, in-vitro excystation with bile salts and trypsin, and cell culture using the Foci Detection Method. Mouse infectivity was also evaluated. All four assays were capable of ascertaining a decline in oocyst viability following UV treatment. The mean percent inactivation using DAPI/PI and excystation (based on sporozoite yield) was 50.24 (plus or minus 12.39) and 78.13 (plus or minus 20.47), respectively. A limitation to assessing viability by DAPI/PI and excystation was that a maximum of two logs inactivation could be determined. The cell culture Foci Detection and mouse infectivity methods were more sensitive than either vital dye staining or excystation, with both showing a greater than 4 log10 inactivation. This study suggests that inactivation should be assessed using infectivity methods and that cell culture is a reliable alternative to animal models.

Product Details

Published:

01/01/1998

ISBN(s):

0898679796

Number of Pages:

7

File Size:

1 file , 80 KB