Measles detected in Sacramento County wastewater samples; no confirmed cases so far
Sacramento County officials warned healthcare providers about recent detection of measles virus in local wastewater samples.
Measles markers were detected in samples collected by the Sacramento Area Sewer District (SacSewer) on May 20 and 21, according to the measles health alert shared by the Sacramento County Public Health (SCPH).
SacSewer confirmed the presence of measles in its sewage surveillance testing samples on two additional days, May 22 and 24. In a recent statement shared via email by Nicole Coleman, the director of communications at SacSewer, there were no detections on May 23, 25, 26 or 27.
“The presence of this marker indicates that at least one of the 1.6 million people we serve throughout Sacramento County and the City of West Sacramento was actively shedding the virus,” the statement said. The exact location of the viral sample cannot be determined, and it remains unclear whether one or multiple individuals were the source.
The testing efforts are part of a proactive sewage monitoring project between SacSewer and Stanford University checking for various viral markers.
Bay Area officials warned of potential measles exposures after one adult tested positive last week.
According to Dr. Olivia Kasirye, the Sacramento County public health officer, there are no confirmed measles cases in the county.
She said people should take this finding seriously, especially considering that there have been outbreaks in other parts of the country, most notably Texas. She encouraged vaccination as the best protection against measles, for which there is no treatment but rather management of symptoms.
She also noted the risk of exposure to travelers, citing at least three cases in California last year resulting from international travel.
Kasirye noted that the measles, mumps and rubella (MMR) vaccination rate for school-aged children in the county is above 95 percent. This benchmark provides the necessary protection levels against community spread, according to the California Department of Public Health (CDPH). High vaccination rates are common statewide.
In California, 11 confirmed measles cases were reported for the year across seven jurisdictions as of May 26, according to the CDPH. Zero cases were reported in May.
Nationwide, the Centers for Disease Control and Prevention (CDC) reports 1,088 cases across 33 jurisdictions as of May 30.
Kasirye urges the public to be alert and aware. If someone is developing symptoms, she encourages isolation and reaching out to healthcare providers to decide the best course of action.
Early measles symptoms include fever, cough, runny nose, and red, watery eyes, as shared in the SCPH alert. The characteristic measles rash then appears three to five days after the initial signs, starting on the face and then spreading to the rest of the body.
For more information on the measles virus, please visit the following resources shared by SCPH:
Any known or suspected measles cases should be reported to Sacramento County Public Health at (916) 875-5881.
This story was originally published May 30, 2025 at 2:23 PM.
