Icddr,b and partners have introduced the first-ever sewage surveillance system for SARS-CoV-2 RNA in Dhaka, which can successfully track COVID-19 in sewage or wastewater.
The finding was revealed at a dissemination seminar held at Six Seasons Hotel in the capital on Monday. It was funded by the Bill and Melinda Gates Foundation.
The Dhaka-based international health research centre popularly known as -icddr,b, University of Virginia, USA; Imperial College London, UK; Institute of Epidemiology Disease Control and Research (IEDCR), Bangladesh; the Directorate General of Health Services (DGHS), Bangladesh and partners have presented the new system.
The sewage surveillance system covers 33 different catchment areas in eight wards of the Dhaka North City Corporation (DNCC) and was started in June 2019, initially for poliovirus (Sabin vaccine strains), antimicrobial resistance genes, and other enteric pathogens.
When the COVID-19 pandemic broke out in March 2020, the scope of the system was immediately expanded to test samples for SARS-CoV-2 virus. Since then, weekly sewage samples are collected from each catchment area and the amount of viral pathogen in the system is quantified using a method called reverse transcription-quantitative PCR.
The viral load associated with each sample collection site is then connected to its watershed through sewage and drainage line tracing and provides a measure of how many infected people there are in the area.
Finally, all these data and analysis are presented through an online dashboard hosted at the following link https://dhakacovidtracker.research.virginia.edu/.
The surveillance system works as an early indicator, which allows public health officials to predict an increasing or decreasing trend of infection around a week prior to the rise or fall in COVID-19 cases.
With this knowledge, public health officials can visualize, which regions have a higher prevalence of COVID-19 and can allocate more of their limited testing resources to those areas and prevent further transmission.
They can also implement public health interventions specific to a particular location and keep the citizens of the community as safe as possible.
“COVID-19 disease diagnosis currently relies on sick people to seek medical help, but many sick people do not seek help, many are also asymptomatic, thus authorities often remain unaware of the total number of infected individuals, leading to an underestimation of the community transmission of COVID-19. Active surveillance system like ours, which do not rely on the actions of sick people can help address outbreaks of infectious disease, such as COVID-19 more effectively” said Dr Rashidul Haque, Senior Scientist at iccdr,b.
“This type of research being done on the sewerage system is very new to Bangladesh. We may be able to disseminate the findings internationally and show the world how we can do surveillance through sewage systems.” said Mr Syed Mojibul Huq, Additional Secretary (Public Health Wing), Ministry of Health & Family Welfare.
“The new system will definitely contribute to creating awareness and the research findings can be translated into action and impact policy and programmes regarding Covid-19 containment,” said Brigadier General Md Zobaydur Rahman, Chief Health Officer of Dhaka North City Corporation.
Dr Mami Taniuchi, Associate Professor from the University of Virginia said, “We are establishing a robust system to track circulating strains and variants of SARS-CoV-2. We initiated the work and are presently analyzing the data. Hopefully, these insights will also help identify changes in transmission more accurately and help strengthen public health measures and surveillance for COVID-19.
Professor Meerjady Sabrina Flora, Additional Director General, DGHS said, “The COVID-19 pandemic is not ending anytime soon, we need to get ahead of it and thus must keep the rapid community transmission in check. As the number of asymptomatic cases is more than symptomatic cases, this type of surveillance system is really useful for the government of Bangladesh.”
icddr,b’s Executive Director, Dr Tahmeed Ahmed said, “Bangladesh has done pretty well in containing Covid-19 because of the efforts of the government. The different types of innovative research being done in Bangladesh on Covid-19 are also supporting the government in its efforts.”
