Officials say possible hantavirus case in San Quentin prison was false positive

A reported possible case of hantavirus in an inmate at the San Quentin Rehabilitation Center in California was determined to be a false positive after further laboratory testing, officials said Friday.

Authorities investigating a potential case of the rare-but-deadly disease initially sent a sample from an inmate to a commercial lab for antibody testing, and the result was positive, according to a statement from the California Department of Public Health, which coordinated the investigation along with the California Department of Corrections and Rehabilitation and Marin County Public Health.

"Because false positives are common as antibody tests can sometimes cross-react with other viral infections, CDCR provided a sample to CDPH's Viral and Rickettsial Diseases Laboratory, which performed PCR testing that was negative for hantavirus," the statement said. "With this result, and further investigation of the individual's full clinical information and laboratory testing results, CDPH has determined that this is not a case of hantavirus and that the commercial lab's result was a false positive."

The Times reached out to the San Quentin Rehabilitation Center but did not receive a response before publication.

The prison is designed to hold more than 3,000 individuals and currently houses low- and medium-security inmates, according to the CDCR.

Officials have decontaminated the facility's inmate housing as a precaution and medical staff are monitoring prisoners and staff, The Mercury News reported.

Though hantavirus cases are rare, several have been making headlines of late.

Five California residents were exposed to a strain of the hantavirus, known as Andes virus, that spread on a Dutch cruise ship and killed three people.

Typically, hantavirus spreads by inhaling particles contaminated with the urine, feces or saliva of wild rodents.

The Andes virus, that was spread on the cruise ship, is a strain of the hantavirus that's spread from human to human.

There have been 890 laboratory-confirmed cases of the lung-attacking disease reported in the United States since surveillance began in 1993, according to the most recent data from the U.S. Centers for Disease Control and Prevention.

The data suggest that contracting hantavirus is rare, said Dr. Afif El-Hasan, a member of the American Lung Assn.'s national board of directors.

"That being said, it's probably underdiagnosed because the symptoms are a lot like the flu or other illness," El-Hasan said. "And a lot of people may have passed away or had hantavirus, but it was never diagnosed."

There is no vaccine or specific antiviral medicine for hantavirus.

Intensive care treatment may include intubation and oxygen therapy, fluid replacement and use of medications to lower blood pressure, according to the American Lung Assn.

Last year, when actor Gene Hackman and his wife Betsy Arakawa were found dead in their New Mexico home, authorities determined that Arakawa had died by complications caused by the hantavirus, with evidence of rodents on the property.

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This story was originally published June 12, 2026 at 12:21 PM.