It also can survive for hours on plastic surfaces, a WHO investigation finds The Hong Kong government yesterday was urged to step up monitoring of the sewage system after a WHO investigation found that the Sars virus could live for up to four days in human waste. The World Health Organisation (WHO) yesterday released findings from a network of laboratories that showed the virus that causes severe acute respiratory syndrome (Sars) could live for days in faeces and urine. The studies by laboratories in Hong Kong, Japan and Germany also found the virus can survive for hours on common plastic surfaces outside the human body at room temperature. Klaus Stohr, WHO's scientist for Sars in Geneva, said: 'We now have scientifically substantiated data on the stability of this virus in the environment. What is surprising is that this virus can stay alive for at least four days in stools under normal room temperature, particularly in stools from diarrhoea patients.' Dr Stohr said that the findings supported an earlier report by the government into the Amoy Gardens outbreak in March that said faeces were the source of transmission. It had previously been thought that people could only become infected through coughing or sneezing. 'A break in the sewage pipe could perhaps be an explanation,' Dr Stohr said. Malik Peiris, chief of virology at Hong Kong University, said the findings underlined the oft-repeated message of keeping hands clean. 'It is even more important now because the virus will not die out. Unlike other respiratory viruses which generally die out in a few hours, the coronavirus seems to be tougher ,' he said. Rudolf Wu Siu-sang, director of the Centre for Coastal Pollution and Conservation of the City University, said closer attention to the sewage system was needed. He said it took only three to four hours for Sars-laden waste to travel from a domestic toilet to the marine outfall. 'If there is an outbreak the concentration [of the virus in the water] will be high and could infect more people,' he said. 'The best way of dealing with this is to refrain from eating [local] shellfish, or cook it very thoroughly,' he said. 'Refrain from going to beaches or swimming areas where the E-coli count is high. Sars makes it more dangerous than before.' E-coli counts show the extent of faecal contamination of water. A spokeswoman for the Environment, Transport and Works Bureau said: 'The sewage should have been diluted many times when it arrives at our treatment plant and should not pose much risk.' But the Drainage Services Department has stepped up its monitoring and the Environmental Protection Department regularly monitors beach water quality, she said. The Department of Health said it welcomed the findings, but it would not change the anti-Sars measures already in place.