ENVIRONMENTAL HEALTH
Wastewater Surveillance: Signs of Success for a New System
By Erin Morin, MHS, specialist, Environmental Health
Kayley Janssen from the Wisconsin State Laboratory of Hygiene pipettes sewage samples. Photo: Wisconsin State Laboratory of Hygiene.
During the COVID-19 pandemic, wastewater surveillance emerged as a useful public health tool to understand the presence of pathogens and their trends, as well as variants of diseases by analyzing samples of a community’ s wastewater. Agnostic of healthcareseeking behavior and symptom presentation, wastewater surveillance can fill gaps in existing clinical surveillance systems, provide early warnings for healthcare facilities, help determine resource prioritization, and offer insight into the next public health threat.
Since 2021, the US Centers for Disease Control and Prevention’ s( CDC’ s) National Wastewater Surveillance System( NWSS) has funded 50 states, five cities, two territories and one county to develop wastewater surveillance programs. These jurisdictions have built capacity from the ground up to cover 45 % of the US population and have used wastewater surveillance to detect targets such as SARS-CoV-2, influenza A / B, RSV, mpox and even polio. While wastewater surveillance is not a silver bullet and might not be effective for every pathogen, many jurisdictions have successfully used the data to implement routine and outbreak response public health interventions in their communities. These actions would not have been possible without NWSS funding and technical assistance.
Success Stories in the West …
The Houston Health Department( HHD) and their academic partner, Rice University, had been testing weekly wastewater samples for measles for about a year before they detected the virus in wastewater. The positive detection was in a sample collected before a clinical case was reported. In a parallel investigation, two cases of measles were confirmed in unvaccinated adults who had recently traveled internationally and resided within the sewershed of the positive detection. There have not been any subsequent positive wastewater detections in the Houston area— although they still test— and the method developed on collaboration with Rice was used in the West Texas outbreak and successfully identified measles in New Mexico’ s wastewater, per their statewide HAN.
Within a month of the first diagnosed US mpox case in May 2022, WastewaterSCAN validated an existing clade II mpox virusspecific assay that was then deployed in routine wastewater testing. Mpox was detected in multiple communities’ wastewater throughout California within days of the assay implementation. Those detections helped inform public health understanding of the state and community burden of disease as clinical testing began to scale up and intersected with increasing awareness of the disease in at-risk populations. The California Department of Public Health( CDPH) worked closely with WastewaterSCAN to notify local health departments, who then alerted health care systems and local medical providers. With this information, they were able to allocate resources( vaccine, therapeutic and testing resources) and enhance community outreach. CDPH has since added the mpox clade II assay to their own routine wastewater testing. As the initial outbreak waned, wastewater surveillance for mpox has continued to prove useful, identifying mpox in the wastewater prior to case ascertainment, enabling scaled-up outreach and communication to mitigate further spread. Wastewater surveillance was again able to be leveraged in 2024 in response to the clade I mpox public health emergency of international concern.
… and the East
The Virginia Division of Consolidated Laboratory Services( DCLS) recently expanded its testing capacity to include SARS-CoV-2, influenza A / B, RSV, and mpox clade I and II. By bringing these assays in-house, DCLS improved turnaround times and reduced the reliance on external reference laboratories. This supports faster, more integrated public health responses and strengthens Virginia’ s overall preparedness for respiratory and emerging infectious disease outbreaks by providing more accurate, timely and complete data.
While all eyes were on the 2025 NFL Draft, the Wisconsin State Laboratory of Hygiene( WSLH) was looking at wastewater from treatment facilities in the area. As a part of their large events monitoring, they tested the wastewater for 13 pathogens of public health concern over an 8 1 / 2-week sampling period( six weeks before the event, three event days and the following 2 1 / 2 weeks) using a combination of digital PCR
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