By candace.tyler in Stories May 10, 2024

Wastewater Surveillance Deep in the Heart of Texas


The top public health official for Dallas County, Texas, explains why he trusts wastewater surveillance data to track COVID and other infectious diseases in Dallas County.

Dr. Philip Huang is a public health champion and a trained scientist. Since 2019, he has served as the Director and Health Authority for the Dallas County Health and Human Services Department. He earned his medical degree from the University of Texas Southwestern and his master’s in public health from Harvard University. The data Huang analyzes, and the public health decisions he makes based on that data, affect the lives of more than 2.6 million Dallas residents every day.

When the pandemic first emerged, the County of Dallas instituted a then-new scientific regimen of testing untreated sewage from five Dallas-area wastewater treatment facilities for the presence of genomic material from SARS-CoV-2, the virus that causes COVID-19.

As soon as Huang heard about the potential of wastewater monitoring, he was intrigued. “We were interested in doing whatever we could with wastewater. We explored trying to do it on our own, but it looked very expensive,” he says. The University of Texas Southwestern was interested, too. Fortunately, we were able to connect with the CDC’s National Wastewater Surveillance System (NWSS). “It was nice that there was this opportunity to participate in these other national efforts with less economic cost,” he recalls. In 2022, that deepening interest in the wastewater science would lead Huang to partner with WastewaterSCAN’s monitoring program as it rolled out nationwide, first collecting samples in nearby Garland and Sunnyvale before getting approval from the City of Dallas to participate.

The fast-developing science of wastewater-based epidemiology (WBE) has become a reliable data source for Huang, offering critical data insights to the health guidance he provides to Dallas County.

Growing Trust

Huang is impressed by WastewaterSCAN’s science. It is rigorous, proven, and reliable. Most importantly, he appreciates that the wastewater data on pathogens warns him of emerging outbreaks a week or two in advance. If it’s in the wastewater, it’s in the community. Whether wastewater data indicate local infections levels are trending up or down, it won’t be a surprise.

“It is very reassuring to see that the wastewater testing shows that we aren’t missing COVID in our clinical test results or that doctors weren’t picking it up,” Huang says.

Huang relies on WastewaterSCAN’s proven science and easy sampling methods, but it is the access to user-friendly data that has most changed Huang’s work. “It’s really easy to look at all the different things we’re monitoring and see what the trends are,” he explains.

The typical 72-hour turnaround from collecting wastewater samples to reporting the results, the easy-to-understand graphs and charts on individual pathogens, and the 24/7 availability through an easy-to-navigate web-based data dashboard, have all served to quickly turn WastewaterSCAN into a go-to resource that complements the other data Huang uses to communicate to County leaders how they should address the pathogens in the community.

“During COVID, I really grew to appreciate how WastewaterSCAN makes the data much more user friendly,” says Huang. “I can attest to using the charts and data in my regular presentations to the Dallas County Commissioners Court to keep them apprised of what we are seeing related to COVID-19 and other monitored pathogens.”

The Complete Picture

Wastewater data is not Huang’s only scientific tool. He relies on a steady flow of resources from labs, local hospitals, reports from their phone bank, and the CDC. But wastewater testing provides that extra level of assurance that helps him sleep better at night.

“We are doing a lot of data modernization right now—a whole integrated system. We’re bringing it all in, matching and merging, monitoring,” Huang says. “Every Monday we have a command team call where we ask, ‘What are you seeing in the wastewater, in the ERs, on the phone banks, in the syndromic surveillance and so forth?’ Just always trying to stay ahead of things.”

WastewaterSCAN data is now a critical component of Huang’s network of data sources, in addition to electronic reports from labs, electronic case reports from hospitals, mortality data from the vital records department, and immunization data from the state.

“Every time I make a presentation to for Dallas County Commissioners’ Court, wastewater testing is an important tool behind the recommendations that I make to the commissioners, and often the media will pick it up,” Huang says of wastewater monitoring’s expanding influence. “They get it. They appreciate it. It’s very straightforward.”

COVID-19 aside, Huang has watched with interest as WastewaterSCAN has steadily added to its list of pathogen targets—influenza, mpox, norovirus, Hepatitis A, Candida auris and more. With each one, Huang’s trust in the science grows.

During last summer’s national mpox outbreak, for instance, the wastewater data proved helpful in monitoring the situation in the Dallas area, Huang explains, particularly during a local four-day circuit festival in the gay community, which is at higher risk of mpox. There was fear that the festival would contribute to a spike in mpox cases.

The Department mobilized teams to provide vaccines and education to the community, and Huang continued to monitor the WastewaterSCAN mpox data closely. Through the wastewater and other surveillance data available, Huang was reassured to see that Dallas County was not experiencing an increase in mpox cases or wastewater signal. The data proved reliable, and the festival came and went with just one confirmed case of mpox.

“I really value it and appreciate WastewaterSCAN. I can’t say we’re going to get rid of our [other] core surveillance activities, but wastewater testing definitely has a role,” Huang says. “It is a great tool.”

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