Sewer Sentries: robust surveillance for SARS-CoV-2 genes in wastewater

A wastewater-based health surveillance system for early detection, appropriate resource mobilization, and spatial monitoring of outbreaks to assist the Government to take preventive and mitigation measures to contain the Covid-19 outbreak. 

Ms. Hasin Jahan, Country Director, WaterAid Bangladesh

The global COVID-19 pandemic has spread to 221 countries and territories, with 135 million confirmed cases and more than 2.9 million deaths worldwide, as of April 12, 2021. Due to lack of sufficient diagnostic testing capacities and large number of asymptomatic/oligosymptomatic patient, there is significant ambiguity regarding the extent of SARS-CoV-2 infections.

Dhaka is the capital of Bangladesh with the highest population count of about 21 million. Dhaka is considered to be the epicenter of the disease, accounting for 61.5% of all cases in the country as of April 11, 2021. From the first week of April 2021, a new record of infections and deaths are being recorded everyday. 22% of the conducted tests are now showing positive infections of COVID-19. Therefore, having this in the backdrop, molecular method RT-PCR (reverse transcription polymerase chain reaction) based detection of SARS-CoV-2 in wastewater could be an important strategy to monitor the prevalence of the disease/pathogen in the community and utilize this information for setting appropriate response strategy by the health sector.  

Sanitation-related disease, lack of access to safely managed sanitation or appropriate wastewater treatment hinders the progress under the Sustainable Development agenda. Cities/Small towns/municipalities and regions that are still defecating in the open and mostly have non-sewered/unimproved and limited sanitation services, and people from the urban slums are considered as target group. Guidelines and tools on sanitation and health, using risk assessment to identify, prioritize, manage, and monitor coordinated action to protect public health are essential. The tool and approaches under this initiative is targeted to address COVID-19, in future with some enhancement it will be immensely helpful for predicting other diseases using wastewater-based approaches.  This initiative will assist health ministry and other relevant stakeholders to upgrade the COVID-19 surveillance system to monitor the actual situation of the pandemic and to enable early identification and spatial monitoring of future outbreaks. 

At the same time, it can also be used to confirm the elimination of viruses or long-term surveillance for appropriate resource mobilization. The nationwide wastewater-based health surveillance system will enable us to tackle such pathogens in advance so that it can serve as an early warning tool to avoid future disasters. 

This is a solution for the enhancement of country’s health system and the government of Bangladesh already shared their dashboard publicly. Our solution will be embedded to this dashboard and shall be used by the government to assess community health determinants which requires real-time monitoring results. Hence, the forecasting will help both government and people to respond, set action plants and resources mobilization.

In Bangladesh, various local communities are unaware of spreading diseases in their locality, even in areas where health education is prevalent to some extent. Hence, everyone in the community, rich or poor, are affected when there is a disease outbreak. For example, a slum area in Bangladesh where health intervention is very poor, very little is known about their health situation. Likewise, the poor population is underserved in Bangladesh and other developing countries. If we could include all these communities in wastewater-based surveillance, monitoring results will help regulatory authorities for intervention to minimize health burden. 

During this pandemic crisis, we identified presence of SARS-CoV-2 in wastewater of certain areas and expanded activities from one district to fourteen districts of Bangladesh including the Rohingya camps. There we have investigated presence of SARS-CoV-2 in wastewater and different other abiotic and biotic parameters that can influence presence of SARS-CoV-2 in wastewater. Moreover, the wastewater-based health surveillance system will monitor presence of water-borne diseases or outbreaks of various diseases by collecting samples from different areas around the country. The specific objective is to collect samples at certain intervals and ensure indicator-based solutions upon laboratory findings for community regarding health and sanitation. 

Currently, we are collecting sewage water samples from 16 localities of Bangladesh as a pilot study just to mature the idea of our plan to have wastewater-based health surveillance system for the country over the period of 3 years, if we receive the funding from this prestigious source.  

We have already reached around seven divisions of Bangladesh with our limited capacity of funding. If the solution gets awarded, we are planning to scale into all divisional cities and completely dedicating next one year in building a surveillance network and enabling information through dashboard. After three years and having strong monitoring network for Dhaka and other divisional cities, we may plan further to scale up our impact of the idea by reaching all the communities residing in every district of Bangladesh within shortest possible time.

It will be a proactive approach where millions of lives will be saved by giving early warning of the diseases. For example, government is taking initiatives to observe the number of patients in different hospital during diarrhoea season as an alert system. As the wastewater-based early warning tool shall inform us about diarrhoea epidemic in real-time, the government will get adequate time for decision making.

Firstly, we will monitor the disease prevalence in areas by regularly taking samples from the areas and understanding the intensity of the outbreak through some indicators which will be color-coded as red, yellow, and green. Red representing high prevalence, yellow representing moderate prevalence, and green representing low prevalence of the catchment area. We will establish direct reporting system for laboratory to the dashboard to enable quick and smooth transition of data and results to the public, local administration/committee and decision makers. 

This local committee will act as another monitoring tool consisting of local administrators, government, health personnel, NGOs, and civil society at the community level. The local committee will have access to all this monitoring data and test results so that they can take/recommend adequate measures at the right time in order to make to prevent the future threat. For example, if the laboratory findings in the system indicate a rise in outbreak of COVID-19 in an area, the local monitoring committee will immediately take necessary actions like restricting people's movement and supplying essential medical supplies to the local health care facility or hospital. The committee can also undertake awareness raising campaign for handwashing and other hygienic behavior. 

The forecasted barriers and challenges in the context of decision support and integration of SARS-CoV-2 RNA testing in wastewater primarily lies within the existing surveillance’s legal framework in Bangladesh, which is currently absent. In the context of Bangladesh the current barrier is the challenge of lack of resources for regular monitoring. This prevents the decision makers with a wholesome picture of the COVID-19 spread trend. The inclusion of un-sewered sanitation systems in surveillance programming is another critical barrier. This is mainly a policy and technical challenge. The current health policies are not equipped with adoption of the results generated by a waste water based surveillance technology. To mitigate this, WaterAid Bangladesh have already signed MoUs with the relevant departments of the government to ensure that the surveillance result outputs are taken into current and future policy consideration. Furthermore, the time gap between the sampling and the availability of test results is another challenge. This may not allow early warning and taking response measures in timely manner. To mitigate this, WaterAid and its partner organisations will explore technology partnerships with agencies which are able to provide quicker test result yield.

North South University 

Developed countries possess improved sanitation systems and are able to isolate greywater from faecal sludge. In Bangladesh, shared sanitation, poor faecal sludge management (FSM), unaffordability of appropriate on-site sanitation (OSS) contributes to the sanitation crisis. Due to the mixed type of sanitation system, sewage and grey wastewater are open directly to the environment. 

Moreover, in the low-and middle-income countries like Bangladesh where clinical testing of SARS-CoV-2 is unaffordable for mass individuals, there is inadequate capacity and facility for testing, insufficient supply of personal protection equipment, poor public sanitation practices, poorly managed public health care system and services, lack of public awareness, and a large population vulnerable (e.g., urban slums, Rohingya refugees) to community transmission. 

We have already detected and isolated SARS-CoV-2 viral RNA from multiple sanitation sources. Still, there is a big gap yet to identify what happens in the transit time of SARS-CoV-2 viral RNA after shedding out in the feces to reach the environmental recipient. Monitoring wastewater has the potential to reveal useful epidemiological information and scale-up of wastewater-based health surveillance in Bangladesh. 

• North South University (NSU) is the main implementing partner responsible for project management, analytic interpretation, and the tracking of potential mutations in virus genetic material (RNA). 

• Noakhali Science and Technology University (NSTU) contributes with their unique lab facilities for RNA isolation and reverse RT-PCR analysis along with sample preparation, and analytic interpretation. 

• KTH Royal Institute of Technology (KTH) will be leading the role for enhancement of protocol, methods development, and analytic interpretation. 

• Director Generals Health Service (DGHS) has different departments, importantly IEDCR is the responsible institute to carry out the surveillance system in collaboration with another department. DGHS MIS section will support the endeavour by providing clinical case information on a regular basis and updating data from wastewater-based surveillance. DGHS hospital section will be actively engaging and provide hospital access for sample collection as and when needed.  

• Dhaka Water and Sanitation Authority (DWASA) is the lead organisation for water supply and sewer system of Dhaka city. DWASA will be an active partner and collaborate by giving access to sewer system and water supply information. 

• ITN-BUET will actively participate in the technical meeting and guide as and when required.  They will also review the technical document and participate in the dissemination.