Detecting SARS-CoV2 using Houston’s wastewater

Researchers at Baylor College of Medicine, in partnership with the Houston Health Department and Rice University, have determined that testing the city’s wastewater for SARS-CoV2 provides a significant lead-indicator for the prediction of outbreaks at the regional level.

The researchers have been studying samples of wastewater collected by Houston Public Works. Using existing and newly established testing methods, they were able to identify the presence of the novel coronavirus in wastewater samples collected on a weekly basis from late May to the present from most of the 39 sites throughout the city.

Since there is evidence that coronavirus is shed in a person’s excrement, wastewater sampling is a cost effective, efficient, and highly comprehensive mechanism to capture total viral levels in the Houston population, with data down to the community and neighborhood level. In addition, such an approach is thought to capture those who shed the virus before symptoms are present or are asymptomatic carriers.

The effort at Baylor was spearheaded by microbiologist Dr. Anthony Maresso, director of BCM TAILOR Labs, the College’s initiative that specializes in quickly adjusting research efforts to meet infectious disease needs.

The data produced by the team enables city health officials to mobilize to the specific areas identified by the researchers as an at-risk area for a surge by increasing nasal testing, isolating congregant living facilities and implementing local education aimed at reducing community transmission. Many cities and governments have now implemented such programs across the global after several groups, including Houston’s, showed its predicative attributes. This also includes effluents coming from plants, schools, campuses, hospitals or other institutions.

“This is not Houston’s first infectious disease crisis,” said Maresso said. “Wastewater sampling was pioneered by Joseph Melnick, the first chair of Baylor’s Department of Molecular Virology and Microbiology, to get ahead of polio outbreaks in Houston in the 1960s. This work essentially ushered in the field of environmental virology, and it began

here at Baylor. TAILOR Labs is just continuing that tradition by providing advanced science measures to support local public health intervention,” Maresso said.

“It’s a cost effective way to gauge Houston’s total viral load. It tracks well ahead of positivity rate, 10 days in some cases,” said Dr. Austen Terwilliger, director of operations at TAILOR. “At the moment, we are at the lowest viral levels since we started sampling, which is excellent news.”

“The massive scope of data we’ve collected and analyzed with the city of Houston and our Rice counterparts has allowed us to have what is perhaps a unique level of confidence in what we’re reporting,” said Dr. Justin Clark, TAILOR’s data scientist.

The researchers hope to continue the program well into 2021 and even adapt the approach to other seasonal viruses or drug-resistant bacteria in hospitals.

Update as of July 2021:

The wastewater surveillance data has used by the Houston Health Department to respond to viral outbreaks in real-time for nearly 15 months, efforts that included sending strike teams to effected areas to strengthen public health strategies. Other cities around the world have now emulated the approach that began here in Houston.

Maresso and TAILOR Labs are now adapting the effort to survey for other viruses and bacteria of importance, including the tracking of HIV and possibly other respiratory viruses such as the flu. This work, pioneered to detect SARS-CoV-2, has the potential to contribute to the ending of other decades-long epidemics.

“We are at a unique crossroads with our war on viruses and bad bacteria,” Maresso said. “Wastewater monitoring will give us a novel and paradigm-changing advantage, particularly because this approach samples a population, not the individual, in an unbiased way. It is like being able to see the enemy all at once, monitor its movements and negate its sneaky ability to go undetected.”