Solar UV reduces Cryptosporidium parvum oocyst infectivity in environmental waters.

This study sought to determine the effect of solar radiation on Cryptosporidium parvum in tap and environmental waters. Outdoor tank experiments and a cell culture infectivity assay were used to measure solar inactivation of C. parvum oocysts in different waters. The results concluded that Solar UV can rapidly inactivate C. parvum in environmental waters. This is the first study to assess natural sunlight inactivation of C. parvum oocysts in surface waters and drinking water using an infectivity measure and determines the wavelengths of light responsible for the inactivation. The findings presented here provide valuable information for determining the relative risks associated with Cryptosporidium oocysts in aquatic environments and identify solar radiation as a critical process affecting the oocyst survival in the environment. Journal of Applied Microbiology. 2008;(104):1311–23.