Wastewater monitoring detects pathogens in Detroit's population and has helped monitor and predict disease outbreaks since 2017

Wastewater monitoring reached a significant breakthrough through the height of the COVID-19 pandemic, when authorities began using the technology to Monitor local virus levelsBut my colleagues and I had been exploring the potential of wastewater as a public health tool years before anyone had heard of SARS-CoV-2.

My Environmental Virology Laboratory based at Michigan State University is in a partnership with the City of Detroit and the Great Lakes Water Authority since 2017, after we began Testing of municipal wastewater from Wayne, Oakland and Macomb counties to analyze viral diseases within the greater Detroit area.

Imagine you desired to discover a potentially emerging infectious disease in an urban area before an outbreak occurred. Could you recurrently collect clinical samples from everyone locally and test all of them for each possible virus? No, that’s an unimaginable task.

Instead, we collected municipal wastewater, as a representative mixed sample from the community and tested this with advanced molecular methods to Detection of endemic and emerging virus-related diseases circulating within the region. We identified viral genomes related to several Gastrointestinal, respiratory, blood and vector diseases excluded from the population. We have Herpes virusesincluding rare species, and we identified peak of hepatitis A outbreak by wastewater evaluation that occurred before peaks in clinical samples.

The ongoing project in Detroit switched to Surveillance of SARS-CoV-2 in 2020. Our team, later expanded to incorporate local health departments, practicing engineers, and the Michigan Department of Health and Human Services, was capable of discover COVID-19 spikes within the Detroit metropolitan area population five weeks before the outbreak of the Delta variant was visible in positive COVID test data.

Diagram with two large peaks
The tests detected peak levels of SARS-CoV-2 in wastewater (indicated by the orange line) roughly one month before peaks in clinical COVID-19 diagnoses in patients.
Zhao et al. 2022

Our team is continually working to expand and improve our methodology to detect the presence of endemic and emerging communicable diseases within the Detroit metropolitan area population and to predict when and where outbreaks will occur.

Data hidden within the drain

Wastewater is a combination of all the pieces that goes down the drain from the bathroom, shower, laundry, dishwasher or kitchen sink. In most cities, rainwater and water from industrial processes also find yourself within the sewage system.

Municipal wastewater accommodates viruses and other pathogens excreted by individuals with an infection. within the early stages, before symptoms appear.

These microorganisms are diluted in large amounts of water and mixed with soap, personal care products, street runoff, and lots of other chemicals and contaminants. The drop of blood or saliva that a clinic would test for infectious agents is rather more concentrated and far less contaminated with other molecules.

Person in protective clothing and hard hat pouring water into a bucket in an industrial setting
Collecting wastewater samples at a wastewater treatment plant can provide an summary of your complete community.
Irene Xagoraraki, CC BY-ND

Searching for emerging human viruses in wastewater is like in search of a needle in a haystack. We Concentrate and isolate viruses within the wastewater samples. We then extract the DNA or RNA contained within the samples and analyse them using molecular methods like PCR And Next generation sequencingin search of genes related to viruses. Genetic codes indicate which viral infections within the population that produced the wastewater.

Beyond confirming the presence of a pathogen

It is one thing to find out that a a certain virus is present in a community. However, determining how a selected sewage level affects the variety of sick people, or comparing infection rates between communities, is a tougher task. How quickly will a wave of sick people begin if a sewage level is detected?

To predict the timing of outbreak peaksScientists consider several variables, including how much virus a typical patient sheds, how long people shed the pathogen after infection, when clinical symptoms appear and the way long they last, and the way long the pathogen is within the sewer collection pipes. Using all of those aspects, we relate sewage levels to clinical disease levels.

In addition to complex Models that predict temporal fluctuations and peaks in clinical caseswe’ve got developed easy methods for data evaluation that could be used for Decision-making by public health officials. Us too tracked the time delay between SARS-CoV-2 concentrations in wastewater and clinical measurements.

An vital step is to link a certain virus content within the wastewater with the number of individuals living in the realm connected to that sewage system. We use molecules produced by the human body to calculate what number of persons are discharging their wastewater into our sample. For example, using metabolites resembling creatine, 5-HIAA, and xanthine, we calculated COVID-19 trends per capita by relating their levels to virus levels. This process allows for comparisons between communities.

Screening for the following outbreak

Ultimately, health authorities need to forestall any impending outbreak. To this end, developed a rating system to prioritize which notifiable diseases future wastewater surveillance should give attention to.

Clinicians are legally obliged to report dozens of diseases — from chickenpox and COVID-19 to meningitis and measles — to the health department once they are diagnosed. By tracking these reportable diseases, officials can count and record cases and trends.

Our scoring system is one among the primary of its kind. We use 12 aspects, including clinical trends in specific geographic locations and knowledge of how contagious certain germs are. When authorities know which infectious diseases are on the rise in a given community, they will prioritize resources and efforts to watch and forestall their spread.

For example, within the Detroit metropolitan area, we’ve got found that certain diseases, including some sexually transmitted infections, are more common than within the state of Michigan as a complete. It is sensible to focus on resources to handle these diseases.

We also developed a Sequencing and bioinformatics protocola step-by-step process that appears for potentially virus-related sequences which may be circulating locally. This allows surveillance to be prolonged beyond the standard diseases that medical personnel must report back to authorities after diagnosis. This tool can provide authorities early warning if something latest or unexpected appears in wastewater.

Table listing the virus family, virus genus and possibly associated diseases
Examples of virus-related genetic sequences detected in wastewater from the Detroit Tri-County metropolitan area between 2020 and 2022.
Li et al., 2024

Strengthening the scientific basis of wastewater monitoring

Wastewater surveillance has proven itself as an epidemiological tool. However, while wastewater epidemiology has made significant advances in technology, methods, and applications, more must be done to integrate the assorted efforts across the country. For accurate outbreak forecasting, wastewater surveillance databases ought to be integrated with clinical data metrics, behavioral, social, and demographic information, and population mobility data. Close partnerships with local health authorities are critical, as local epidemiologists are those who will use surveillance efforts to tell decision-making.

image credit : theconversation.com