As a microbiologist at Michigan State University and member of the IJC Health Professionals Advisory Board, I spend a lot of time thinking about the relationship between our water and our health. Now more than ever, our health is in the spotlight as the world continues to grapple with a global pandemic. Coronavirus 2019 (COVID-19), also known as the Severe Acute Respiratory Syndrome Coronavirus 2, (SARS-CoV-2) is an airborne pathogen that poses threats to our health. But it is our waters—specifically our wastewater—that helps public health professionals like me to monitor and learn more about the spread and control of COVID-19.
Global Distribution of an Emerging Disease
The ongoing global pandemic of COVID-19 caused by SARS-CoV-2 is a Public Health Emergency of International Concern. Officially declared by the World Health Organization (WHO), this disease has spread quickly and impacted every corner of the globe. Johns Hopkins University has up-to-date data and visuals on its website to see how the novel coronavirus is spreading around the globe.
SARS-CoV-2 is a member of the family Coronaviridae. The virus consists of a group of enveloped viruses with a single-stranded RNA genome. Just as we can identify people by their unique DNA, scientists can identify the virus by its RNA genome.
This virus is related to SARS-CoV-1, which was responsible for the 2002-2003 severe acute respiratory syndrome (SARS) outbreak. Members of this family have been known for some 80 years and cause common colds in humans. Although the main way to spread SARS-CoV-2 is inhalation from person-to-person, it has been shown to spread by hands and objects that spread disease, like doorknobs.
Around the world, leaders must make tough calls about how to monitor the health of, and ultimately reopen, their communities. Getting an estimate of the virus in a community is a challenge when relying on thousands of individual tests. Sewage provides a window to view the infection in a community.
Detecting COVID-19 in sewage
In any good crime drama, detectives rarely catch the perpetrator red-handed at the crime scene. But they find clues, like strands of hair, that can help them identify and find the offender.
When scientists began studying the emerging virus, they did not find the live virus in human feces, but they detected its RNA genome—a clue indicating that the person who excreted the feces is infected. Evidence indicated that this RNA signal also was present in the untreated wastewater in sewer systems en route to the treatment plant.
Concentration and testing for viruses in untreated wastewater has been ongoing for more than 70 years. However, recent advances in molecular biology and genomics have significantly expanded capabilities for wastewater surveillance. A growing number of studies are now helping us understand how samples from untreated wastewater can help generate data about the virus and its spread.
COVID-19 appears to be inactivated as it passes through the colon and is non-infectious in untreated feces and sewage. The process of wastewater treatment, including chlorination, further ensures that the virus materials, like the RNA, are destroyed. Standard wastewater treatment practices are effective and ensure the safety of our waterways and communities.
“Seeing” the virus at the community level
Globally, there have been 39 reports (as of September 13, 2020) of the detection of SARS-CoV-2 in wastewater in Australia, France, Israel, Italy, Spain, The Netherlands and the United States. The health dashboard in the Netherlands highlights the concentrations in sewage and links these to disease in communities.
Wastewater testing and detection can complement individual testing and provide an efficient, pooled community sample, according to the US Centers for Disease Control and Prevention. Sewage surveillance also can be an “early warning” system to alert the medical community to the amount of the virus in a community. Surveillance can help health professionals “see” community patterns such as a decline in infections, or a re-introduction of the virus.
In the Great Lakes region, university researchers in Canada and the United States are investigating SARS-CoV-2 in wastewater. There is now a statewide effort to measure the virus in sewage in Michigan. To understand differences among communities, scientists need to be able to make apples-to-apples comparisons of the data, which requires coordination. The Canadian Water Network spearheads a COVID-19 Wastewater Coalition that helps coordinate surveillance efforts.
There is little doubt that a greater number of forthcoming studies will address virus levels in wastewater and ultimately in transboundary waters, thus providing information on wastewater impacts and the impact of this global pandemic on nearby populations. Thus, as human fecal source tracking and sewage tracking occurs in the waters of the Great Lakes, we will need to be on the lookout for the signal of the SARS-CoV-2 virus as well.
The link between sewage and public health: then and now
The IJC has its own history and experience examining untreated wastewater to respond to public health crises: in 1914 it investigated fecal-related pollution of the boundary waters of the Great Lakes and the potential link between disease and sewage pollution. Back then, untreated sanitary sewers discharged into the waterways—the same waterways where communities got their raw, untreated drinking water. The data from the IJC study highlighted the (at the time, deadly) public health risks of untreated sewage and untreated drinking water.
A little more than 100 years later, while we treat both our sewage and drinking water, we’re still in need of a comprehensive look at the risks and sources of fecal-related pollution of our shared waters. The IJC’s Health Professionals Advisory Board (HPAB) held an expert workshop in 2019 and is working on a project to examine the potential to coordinate a binational, multi-year study of fecal pollution and its sources across the Great Lakes basin. HPAB will post updates about its project to the board’s website.
Researchers like myself and my HPAB colleagues will continue to examine the signals and influences of viruses and pathogens in our sewage, treated and untreated, that flow into our shared waters. As long as we generate sewage, health professionals will have to continue to pay attention to what untreated wastewater is telling us about the status of public health.