Most persons infected with enterically transmitted viruses shed high amounts of virus in feces for days or weeks, both before and after onset of symptoms. Therefore viruses causing gastroenteritis may be detected in wastewater, even if only a few persons are infected. In this study, the presence of nine pathogenic viruses was investigated in sewage (norovirus, astrovirus, rotavirus, adenovirus, enterovirus, Aichi virus, parechovirus, hepatitis A (HAV) virus and hepatitis E virus) to explore whether their identification could be used as an early warning of outbreaks. Samples of the untreated sewage were collected in proportion to flow at Ryaverket (Gothenburg, Sweden). Daily samples collected during every second... More
Most persons infected with enterically transmitted viruses shed high amounts of virus in feces for days or weeks, both before and after onset of symptoms. Therefore viruses causing gastroenteritis may be detected in wastewater, even if only a few persons are infected. In this study, the presence of nine pathogenic viruses was investigated in sewage (norovirus, astrovirus, rotavirus, adenovirus, enterovirus, Aichi virus, parechovirus, hepatitis A (HAV) virus and hepatitis E virus) to explore whether their identification could be used as an early warning of outbreaks. Samples of the untreated sewage were collected in proportion to flow at Ryaverket (Gothenburg, Sweden). Daily samples collected during every second week between January and May 2013 were pooled and analysed for detection of viruses by concentration through adsorption to milk proteins and PCR. The largest amount of noroviruses was detected in sewage two to three weeks before the most patients were diagnosed with this infection in Gothenburg. The other viruses were detected in lower levels. HAV was detected between weeks 5 and 13, and partial sequencing of the structural VP1protein identified three different strains. Two strains were involved in an ongoing outbreak in Scandinavia, and were also identified in samples from patients with acute hepatitis A in Gothenburg during spring of 2013. The third strain was unique and not detected in any patient sample. The method used may thus be a tool to detect incipient outbreaks of these viruses and provide early warning before the causative pathogens have been recognized in health care.
