Santa Clara county health officials revealed Wednesday a measles case at the Google campus in Mountain View.
The visitor, possibly a worker who came down with the virus, is a San Mateo County resident and was at the Googleplex office at 1295 Charleston Road on April 4.
Santa Clara County Public Health Officer Sara Cody confirmed a Google onsite physician contacted the agency to report the case. Health officials then told the Google doctor to share a measles advisory to employees as a precaution.
Health officials said they have not seen any sign the case has caused any others in the Bay Area.
"The vast majority of the population is protected from measles due to vaccination," Cody said. "We're trying to understand 'is there anybody who might have been exposed who's not protected?'"
Since the case is linked to a San Mateo County resident, it is technically not Santa Clara County's case. The latest measles case increases the Bay Area toll to at least eight incidents, and over 20 in California.
Google has not returned calls seeking comment and health officials said an investigation is ongoing.
Here's a look at other recent measles cases in the Bay Area: