[The fate of pathogens in waste-waters]

A large variety of pathogenic organisms capable of transmission by the faecal-oral route may be found in wastewaters. Among the bacteria Salmonella, Shigella, Vibrio cholerae, Yersinia and Campylobacter are the important agents of concern. Also the human enteric viruses (Poliovirus, Coxsackievirus, Echovirus, Hepatitis A virus, Rotavirus) have been shown to be present in domestic waste and may not be completely removed by conventional sewage treatment processes, including chlorination. Discharge of sludge and raw wastewaters in coastal waters is, therefore, potentially hazardous to human health. Enteric viruses generally survive longer than faecal indicator bacteria in water receiving waste and they are detected in seawater which meets current standards for shellfish harvesting. The survival of viruses in seawater depends on a large variety of physico-chemical and biological factors. Viral inactivation process is very complex in nature but it can be interesting to study this phenomenon for better evaluating the true extent of health risk of viruses present in the coastal waters.