Occurrence of Salmonella spp and Cryptosporidium spp in a French coastal watershed: relationship with fecal indicators.

Cryptosporidium and Salmonella are pathogenic microorganisms that can cause severe gastrointestinal illness in humans. Because these organisms are potentially transmitted through natural waters, this study was carried out to estimate the concentrations of both pathogens in a French coastal watershed and to determine the relationships with fecal indicators. Water samples from nine wastewater treatment plants and eight rivers were analyzed. Although both pathogens and indicators are released from sewage effluents, no clear correlation was found between the two enteric pathogens nor between a given pathogen and fecal indicators. These results suggest that fecal indicators do not adequately indicate the presence of Cryptosporidium and Salmonella in natural waters and that pathogens and indicators may have different behaviors in the aquatic environment.