February 15, 2024 | In the future, it may be possible for people to get a read on viruses circulating in their neighborhood in the same way they now do to assess current weather conditions before hitting the road. The means would be some sort of digitized community health report, an early version of which is already being produced for 10 cities across Texas.
The signals come from wastewater collected from public utilities that are being routinely analyzed by experts at Baylor College of Medicine using genetic sequencing and PCR technologies. The viral landscape of human wastewater and its potential to improve understanding of outbreaks and population-level transmission and health effects were described in an article that published recently in Nature Communications (DOI: 10.1038/s41467-023-42064-1).
Wastewater monitoring at this level likely exists nowhere else, according to Anthony Maresso, Ph.D., professor and endowed chair in molecular virology and microbiology at Baylor. “As far as I can tell we are the first to monitor as many viruses of human origin as we can,” which covers all 3,153 known viruses as well as any new mutations of these viruses.
The comprehensive wastewater surveillance program is enabled by a highly systematized process for collecting, analyzing, and interpreting samples and generating reports for public health officials. It is the brainchild of the newly formed Texas Wastewater Consortium, led by scientists at Baylor and funded by the Texas Epidemic Public Health Institute (TEPHI) that was established by the Texas legislature early in 2021 and is spearheaded by the School of Public Health and the University of Texas in Houston.
When the COVID-19 pandemic was newly arising, Maresso and his colleagues at Baylor became one of the first labs in the world to start searching for the SARS-CoV-2 virus in wastewater samples collected from sites in Houston (618,148 people) and El Paso (751,982 people), both of which implemented a city-wide monitoring program. That program broadened to include the entire human virome as well as eight more cities (Brownsville, South Padre Island, Lubbock, Wichita Falls, Baytown, Humble, Missouri City, and Austin) thanks to a partnership with TEPHI. The goal is to expand the network statewide.
Early on, wastewater monitoring efforts turned up an outbreak of monkeypox (now known as mpox)—well before cases started popping up in clinics and in news reports, Maresso notes. Public health officials knew to keep an eye on the newly emerging virus, which was also behaving in never-before-seen ways in terms of transmission.
Health officials have also been forewarned of upsurges in cases of respiratory syncytial virus (RSV) over the past two years, adds Maresso, which fortunately now has a countermeasure thanks to approved vaccines for adults 60 years and older. Wastewater surveillance likewise alerted them when influenza was picking up in the community ahead of individual case reports which, in the years ahead, might also come with a severity timeline.
Few Participation Hurdles
Unlike other states, the public health apparatus in Texas is all connected and operates under one leader, points out Maresso. TEPHI, housed within The University of Texas Health Science Center at Houston, was largely spearheaded by Dean of Public Health Eric Boerwinkle, Ph.D., to strengthen the capacity and resiliency of Texas communities to respond to future infectious disease outbreaks.
As one of the first acting directors of TEPHI, Boerwinkle approached the Baylor team about broadening their SARS-CoV-2 wastewater monitoring program. Since their virus-level detection pipeline was “rather robust,” Maresso says, they readily agreed. The conversation quickly evolved to a discussion about developing an end-to-end pathogen monitoring program, the likes of which was detailed in an article that published early last year in Frontiers in Public Health (DOI: 10.3389/fpubh.2023.1137881).
Thanks in large part to COVID, the benefits of wastewater monitoring are well recognized—no more relying on test-taking by individuals and the reporting network, as well as the ability to get an earlier read on changes in community levels of viral pathogens and emerging variants. Maresso says his lab was particularly interested in detecting all pathogenic threats using technologies already at their disposal.
The Maresso lab collectively receives between 20 and 30 wastewater samples per week (typically a Monday or Tuesday) from the 10 cities, which scientists assess for hundreds of different human viruses, he says. Efforts are actively underway to grow the so-called Texas Wastewater Environmental Biomonitoring (TexWEB) network.
This would be impossible without the Texas Wastewater Consortium, a network of specialists spanning public health, wastewater engineers, communications, forecasting, and methods development, Maresso continues. Their expertise surpasses what the most highly skilled virologists or molecular microbiologists could accomplish on their own.
Expansion of the TexWEB will, first off, require leaders of wastewater treatment plants to enable samples to be sent to Baylor for testing, he says. While some are eager to participate, others are worried about acquiring a “negative image” if anything bad is detected. Participation is logistically straightforward, requiring a bit of time for a person on the ground to gather composite samples and package them for overnight shipping.
Small volumes of wastewater are collected hourly by a fully automated system as it is coming into the plant over the course of 24 hours, adds Maresso. TEPHI covers the cost of sample acquisition, shipping, and testing, which is a “really good” means of lowering the barriers to participation.
The community health reports should prove useful in directing public health education efforts, including geographies experiencing high levels of a vaccine-preventable disease such as polio or measles, Maresso says. If an outbreak is coupled with a vaccine coverage rate below herd immunity level, their response might be to thoughtfully counter misinformation and pushback. There have been historic examples where social media was used as a vehicle for celebrities to cast doubt about the safety and effectiveness of a vaccine, most recently COVID.
Knowing when a virus like SARS-CoV-2 is rearranging and mutating in real time also makes it possible to plan for and prevent serious public health problems, he adds. Researchers can also get a head start on developing new vaccines, tests, and treatments.
Unfortunately, the model built in Texas will be tough to scale elsewhere, says Maresso, due to the required cost and expertise. To reproduce TexWEB in every major city in the U.S. would require not only sequencing and PCR equipment but folks trained to work them. But biotechnology companies could perhaps enter the sector and make headway, he suggests.
Virus-specific wastewater monitoring has on the other hand gained considerable traction, most notably for SARS-CoV-2 but also for influenza and RSV. The Centers for Disease Control and Prevention supports a successful national SARS-CoV-2 wastewater surveillance program linking utilities and public health networks in many cities. In Europe, the U.K., Israel, and Australia similar monitoring programs have also been established and are starting to expand to other viruses, says Maresso, who believes “everybody will converge eventually toward the total virome.”
If these programs are sustained, the near-term possibility is that everyday people will have access to interpretable community health reports about concerning viruses on their cellphone much as they do weather alerts currently, Maresso adds. It will be presented as public information and employ color coding or scales to denote risk level and offer stay-at-home recommendations. Individuals can decide for themselves whether to enter public spaces based on what’s going around and if they have an elderly parent or immune-compromised family member at home who might factor into their decision-making.
“Looking forward, I can envision technologies being miniatured and adapted to home use,” says Maresso. People might provide their own sample to know what is happening in their household, or a cruise line to know what would-be passengers might be carrying aboard. Airlines and airports, as well as hospital systems, might similarly want to screen for potential problems in this more targeted fashion.
“We don’t see insurmountable barriers to these things actually being a reality one day,” he says. The testing device might be a marketed product that people simply blow into to self-assess their risk from viruses in the air.
At the end of the day, for Maresso and his team, pathogen monitoring is about maximizing the amount of information people have at their disposal. “We are not trying to learn about their personal habits, identify information about them, close their schools or places of work. We wish to illuminate the threats out there so that people can a make informed decisions through cutting-edge science and technology.”