Monitoring of Cryptosporidium and Giardia in Czech drinking water sources.

In Czech raw water sources for drinking water supply, Cryptosporidium was found in numbers from 0 to 7400 per 100 liters and Giardia from 0 to 485 per 100 liters. The summer floods of 1997 probably brought the highest numbers of Cryptosporidium oocysts into one of the reservoirs sampled; since then these numbers decreased steadily. A relatively high number of Cryptosporidium oocysts was found in one sample of treated water. Repeated sampling demonstrated that this was a sporadic event. The reason for the presence of Cryptosporidium in a sample of treated drinking-water is unclear and requires further study.