Reflections of IWA WWCE 2024 in Toronto: Bridging Water and Public Health

The COVID-19 pandemic has boosted wastewater testing for information about public health in communities from city to building scale. Also, wastewater surveillance is evolving from polio and COVID-19 to other infectious diseases, antimicrobial resistance and other health indicators. Wastewater-based epidemiological surveillance is an intersectoral activity, where the water sector can mine information for the public health sector. Therefore, both sectors need to be well connected: the water sector can play a pro-active role in demonstrating what information can be mined from wastewater, while the public health sector needs to identify the most pressing needs and added values of wastewater testing for public health data.

IWA launched a new Cluster on Wastewater-Based Epidemiological Surveillance in 2023, and the IWA World Water Congress hosted the first meeting and workshop. The purpose of the workshop was to bring both sectors together to explore the public health value of existing and new targets for wastewater-based epidemiological surveillance. The workshop was well-attended, and the speakers presented strong examples of the added value of wastewater surveillance for public health in different settings.

Global Perspectives on Wastewater Surveillance

The World Health Organization (Batsirai Majuru) presented a tool they are developing for countries to decide which diseases would most benefit from wastewater surveillance, including considerations of feasibility, acceptability, and integration into public health.

RIVM (Ana Maria de Roda Husman) presented examples of the health value of wastewater surveillance in the Netherlands, ranging from tracking polio introductions and spills, monitoring COVID-19 trends, to obtaining comprehensive community-wide data on (rare) antimicrobial resistance in the population.

The Ministry of Public Health in Thailand (Pitiphon Promduangsi) demonstrated how wastewater surveillance provided early warnings of emerging polio circulation, as well as alerts for new COVID-19 waves and the introduction of variants such as Omicron via tourist cities and airports. Additionally, in Thailand, hospital wastewater is used to gain a better understanding of antimicrobial resistance in the population.

The Ottawa Department of Health (Jacqueline Willmore) and water engineers from the University of Ottawa (Robert Delattola) jointly presented the Ottawa/Ontario experiences. Their joint presentation embodied the strong collaboration between water and public health sectors, which has helped create valuable wastewater surveillance programs. During the COVID-19 pandemic, they learned how to use early warning wastewater data for healthcare planning. They have since expanded to other diseases such as influenza and RSV, using the data for healthcare planning and response. They demonstrated how wastewater data on influenza prompted hospitals to strengthen masking guidelines, and how early warning of a new RSV wave in the province of Ontario helped prevent hundreds of children from being hospitalized by starting medication early. Ottawa is now using wastewater for pandemic preparedness by testing for avian influenza (due to outbreaks in cows in the USA) and mpox (in response to outbreaks in Africa).

Workshop participants were invited to reflect on and contribute their experiences with wastewater surveillance for public health in various settings and geographies. While many still associate wastewater surveillance primarily with COVID-19, there are numerous examples of its application to other infectious diseases, antimicrobial resistance, and monitoring of pharmaceuticals, illicit drugs, and more. A significant challenge remains that half of the global population lacks connection to a sewer network (the cluster hosted an IWA webinar last May to share experiences on environmental surveillance in non-sewered settings). Workshop participants concluded that it is crucial to share successful examples of using wastewater data for public health and to continue the dialogue between the water and health sectors to maximize the potential of this valuable disease surveillance tool.