Detecting climate sensitive pathogens via wastewater surveillance program to guide public health interventions in the Cox’s Bazar refugee camp in Bangladesh.

In 2021, icddr,b implemented the wastewater surveillance program in Cox’s Bazar, Bangladesh. Building off decades of evidence which demonstrates the value of wastewater surveillance to detect infectious disease threats, the team collected communal fecal samples and evaluated them for the presence of multiple climate-sensitive pathogens, such as Vibrio cholerae and Salmonella typhi.

In order to deploy this intervention, the team first gained permission to work in the camps along with ethics approvals. A systematic sampling strategy was developed for environmental surveillance by performing scoping visits, key informant interviews and manually mapping, followed by collection and testing of wastewater. Wastewater was collected weekly from open drains and the data was compared with clinical data, when available. Lastly, stakeholders and technical partners were consistently updated with results and progress.

The project overcame many barriers to deploy the solution. As the project faced a cost and timeliness barrier to procuring supplies, colleagues from Emory University personally carried supplies with them from Atlanta to Dhaka. In another instance, the team was not able to collect sub-block level mapping data containing information on drainage and sanitation network, so the team performed manual mapping.

The project was implemented in close coordination and collaboration with the Government of Bangladesh along with other primary partners, including IEDCR, Communicable Disease Control, RRC and DPHE. Other key stakeholders included United Nations organizations (UNHCR, IOM, UNICEF, WHO), who provide regular humanitarian services to the Rohingya refugees and help organize international and national non-government organizations (NGOs).

The project was supported by The Rockefeller Foundation through a grant of $500,000 over two years. Primary costs included lab equipment and consumables, staff time, travel costs associated with sampling, and indirect costs taken from grantee organizations.

The wastewater surveillance program in Cox’s Bazar, Bangladesh has had a significant impact on disease surveillance and control efforts in the area. It has demonstrated the feasibility of conducting wastewater surveillance in settings with limited infrastructure and changing disease dynamics driven by climate change.

The data collected from the program provided the first baseline understanding of disease burden in Cox’s Bazar, enabling health authorities to assess how climate-related events impact spatial and temporal patterns of disease. The program reached 150,000 people across four camps, collecting over 200 samples on a weekly basis from 12 sites. This allowed the team to differentiate between pathogens and monitor their variability over time, upending traditional paradigms of disease surveillance that rely on clinical data.

The wastewater surveillance program has provided a pathway to scalability through government buy-in and ownership, evidence for tailored interventions based on a solid evidence base, and a prioritized focus on equity in disease surveillance in a highly vulnerable community. The program is already being scaled in multiple ways. In August 2022, the Government of Bangladesh and the project’s primary partners announced a joint environmental surveillance effort in two cities, involving five government bodies and multi-lateral organizations.

Globally, over 70 countries worldwide have already conducted wastewater surveillance for SARS-CoV-2, expanding the reach of the polio eradication wastewater network. There is keen interest among other organizations and investors to support the expansion of this program to additional pathogens and genomic sequencing. While the return on investment for this solution is still being evaluated, it is clear that by promptly responding to signals detected in wastewater and implementing targeted interventions, the number of individuals seeking medical care can be significantly reduced, in turn reducing healthcare-associated costs.