Microbiological safety of drinking water

Emerging pathogens in drinking water have become increasingly important dur ing the decade. These include newly-recognized pathogens from fecal sources such as Cryptosporidium parvum, Campylobacter spp., and rotavirus, as well as pathogens that are able to grow in water distribution systems, like Leg ionella spp., mycobacteria, and aeromonads, To perform a risk analysis for the pathogens in drinking water, it is necessary to understand the ecology of these organisms. The ecology of the drinking-water distribution system h as to be evaluated in detail, especially the diversity and physiological pr operties of water bacteria. The interactions between water bacteria and (po tential) pathogens in such diverse habitats as free water and biofilms are essential for the survival or growth of hygienically relevant organisms in drinking water. Results of epidemiological studies together with ecological data are the basis for effective resource protection, water treatment, and risk assessment.