Outbreak of Cryptosporidium hominis following river flooding in the city of Halle (Saale), Germany, August 2013.

Background: During weeks 32-33, 2013, 24 cases of cryptosporidiosis were notified in the city of Halle (annual mean 2008-2012: 9 cases). We investigated the outbreak to identify the source and recommend control measures, considering that between weeks 23-25 the river Saale which flows through the city centre overflowed the floodplain, parts of the city centre and damaged sewage systems.

Methods: We defined a case as a resident of Halle with gastroenteritis, Cryptosporidium-positive stool and disease onset weeks 27 through 47.

[Detection of viruses in raw water as a basic tool for risk assessment].

Human pathogenic viruses may end up in surface waters by fecal contamination. However, the German drinking water ordinance requests that pathogens in drinking water should not be present in concentrations constituting a potential danger to human health. Since many viruses do have a very low dose of infection, they have to be sufficiently eliminated in the process of drinking water purification.

[Special aspects of microbiological monitoring of drinking water quality].

The new drinking water ordinance (TrinkwV 2001) entered into force in 2003. In this paper we report about experiences with monitoring microbiological quality of drinking water. Special problems, for instance requirements concerning the quality of raw water, new and "old" microbiological parameters, microbiological methods, assessment of parametric values, especially in the case of values higher than the imperative value, are also described.