An outbreak detection program found the presence of the measles virus in samples of Houston wastewater in early January 2025, before cases were reported, new findings show.
The findings were possible because almost three years earlier, a team of researchers, including from Baylor College of Medicine, the School of Public Health at University of Texas Health Science Center-Houston, the Houston Health Department and Rice University, had developed an outbreak detection program that analyzes genetic material.
A study using the program then detected the virus in samples collected on Jan. 7 from two Houston water treatment facilities that serve more than 218,000 residents. A parallel investigation confirmed on Jan. 17 that two travelers who contracted the virus resided in the same area serviced by the sampled water treatment plants. More information about the travelers and the facilities was not immediately available.
“In such cases our next step is always validating the signal with a second method, and we were able to do so through a collaboration with the Houston Health Department and Rice University,” said Dr. Sara Javornik Cregeen, a member of the team and an assistant professor in the Alkek Center for Metagenomics and Microbiome Research at Baylor. “They tested for the virus presence in samples from the same date and collection site and confirmed the signal using another technique, PCR.”
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“Because no other cases have been reported and the detections occurred in the same area where the travelers resided, it is reasonable to assume that the measles signal detected in wastewater is from the two infected cases, which underscores the high sensitivity of the method,” said Dr. Anthony Maresso, a member of the team and a professor in molecular virology and microbiology at Baylor.
The researchers are not currently detecting measles viruses in wastewater in Houston, but they are in West Texas cities, where most of the state’s cases are concentrated.
The wastewater detection program that was started during COVID has gotten national attention for its innovation and utility. We’ve used it in the past to help detect the presence of mpox and RSV and the flu, and more recently bird flu. That it was able to detect measles, even that small an amount – just two infected people – is not a surprise but a very welcome and reassuring development. Kudos again to everyone involved.
And here’s your midweek case update.
Texas health officials reported eight new measles cases on Tuesday, with the outbreak spreading to three new counties.
The Texas Department of State Health Services has reported 717 measles cases amid the largest outbreak in the United States in at least 25 years. But the outbreak has appeared to slow recently; Texas reported 26 cases during the one-week period that ended Friday, its lowest one-week total since Valentine’s Day.
Carson County, in the Panhandle, and Collin and Rockwall counties, in the Dallas-Fort Worth area, all reported their first measles cases associated with the outbreak. All three counties reported one case on Tuesday.
There have been 93 people hospitalized for treatment amid the outbreak. Two children, an 8-year-old girl and a 6-year-old girl, died after contracting the virus.
Two-thirds of cases have been in children and teens. Nearly 96% of cases have been in individuals who have not received the measles, mumps and rubella vaccine, or whose vaccination status is unknown.
The DSHS estimated that fewer than 10 measles cases — about 1% of the statewide total — are actively infectious. An individual may be infectious up to four days before a rash appears and up to four days after it’s gone.
The eight new cases reported in Texas on Tuesday includes two in Gaines County. The county has seen 405 cases in total, nearly 57% of all infections connected to the outbreak.
El Paso County also reported two new cases, while Lubbock County reported one. Both counties have now reported 52 cases in total.
The DSHS said there is ongoing measles transmission in eight counties: Cochran, Dallam, Dawson, Gaines, Lamar, Lubbock, Terry and Yoakum.
Of the 717 cases in Texas, 211 have been in children younger than 5 years old and 273 have been in children and teens between 5 and 17, according to the DSHS.
Only 30 cases have been in people who received at least one dose of MMR vaccine prior to an infection.
Texas has also reported 15 measles cases in 2025 that are not connected to the outbreak, most of them related to international travel. That total includes four in Harris County, one in Fort Bend County and one in Brazoria County.
So yeah, definitely slowing. That’s the good news. The bad news, at least potentially, is the continued appearance of the virus in much more populated counties, where the pool of possible victims is so much greater than it was in places like Gaines County. That doesn’t mean that it will start breaking out again in big numbers – these counties have better vaccination rates and more available health care – but it could. We’ll just have to see how it goes. In the meantime, the national case count is now over a thousand. And while that’s a big number, there’s no reason to think that a new outbreak, someplace else a few months in the future, couldn’t easily exceed it. There’s plenty more places like Gaines County out there.