Inactivation of Cryptosporidium parvum under laboratory conditions.

The aim of the present study was to evaluate alternatives for inactivating Cryptosporidium parvum under experimental conditions. Disinfectants against this protozoan are usually based on cresols and often difficult to handle in laboratories. Four different substances (ethanol, denatured ethanol, sodium hypochlorite and peroxide) at different concentrations were tested for several exposure times (30 min, 2 h, 4 h, 12 h and 24 h). The results show an inactivation over 99% by using 10% H2O2 at an exposure time over 2 h as well as 3 and 6% NaOCl after 12 h of exposure. Furthermore, the ability of UV-C light to inactivate oocysts on smooth surfaces (e.g., laminar flow) was evaluated. To mimic laboratory conditions, oocysts were given on germ carriers. Best results (>99%) were achieved at an exposure time of 30 min (100.8 mJ/cm(2)).