A HIGH presence of three enteric viruses — rotavirus, norovirus and adenovirus — in the sewage of the capital, as a study that the Nihon University faculty of medicine and the University of Dhaka conducted has found, comes with reasons for worries. The study, published in the March issue of the International Journal of Food and Environmental Virology, calls the presence of the viruses in sewage ‘alarming’ as they may get into the environment and might get into supply water, putting public health in further jeopardy. The study says, as New Age reported on Thursday, that bacterial diarrhoea caused by vibrio cholerae, escherichia coli, salmonella, shigella and campylobacter is more prevalent in Bangladesh and an added risk of diarrhoea caused by the viruses found in Dhaka’s sewage could further jeopardise public health. This is further worrying as the capital city now faces an unusually high diarrhoeal infection, mostly caused by bacteria. In April alone, the International Centre from Dairrhoeal Diseases Research, Bangladesh treated 23,864 diarrhoeal patients, who are mostly from the capital and its adjoining areas. ICDDR,B physicians suspect the problem to be lying in supply water and the environment.
The Dhaka Water Supply and Sewerage Authority can treat only 20 per cent of the city sewage and discharges the rest into the rivers around the capital city untreated through open, shallow-surface drains not connected to storm sewers. When the drains overflow, the viruses and bacteria get into the environment and surface water, exposing public health to serious threats. Besides, untreated sewage water flowing through surface drains can easily seep into the supply water. The study at hand finds 93 per cent of the sewage samples collected from five roadside drains in the central areas of the capital in June 2016–May 2017 to have contained these viruses. The presence of enteric viruses in sewage is not uncommon but what makes it worrying is their high presence in sewage, which is further compounded by poor or almost no sewage management. The situation calls out the government on shoring up a few issues to head off severe diarrhoeal outbreaks in coming years. A report that New Age published towards the end of April says that the Water Supply and Sewerage Authority has failed to begin the construction of three sewage treatment plants and complete another, three-fifths of which are reported to have already been completed, and renovate the only sewage treatment plant, built at Pagla in 1978, taken up under a 23-year master plan in September 2014. As the city generates more than 2,000 million litres of waste water a day and the existing facilities fail to adequately cater to the need, waste water is managed through septic tanks and soakwells to divert septage and faecal sludge.
The government, under the circumstances, must complete the constructions of the sewage treatment plants already taken up, and 11 more that have been planned, early to head off any outbreak of viral diarrhoea. It must also run test for enteric viruses on supply water, which could be contaminated from sewage seepage, and take steps to ensure safe drinking water.
