SAN MATEO COUNTY (CBS SF) – Health officials in San Mateo and Santa Clara counties on Wednesday confirmed that a person diagnosed with measles recently visited Google’s headquarters in Mountain View, exposing employees.

“That person was actually a resident of San Mateo county,” said Santa Clara County Public Health Director Dr. Sara Cody.

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According to Buzzfeed, the Google employee visited the tech giant’s office at 1295 Charleston Road on April 4. However, a Google physician did not notify employees until April 13th, Buzzfeed reported. It’s unknown why the alert did not happen immediately.

Cody said the investigation into the person’s whereabouts while infected and those potentially exposed is “resource intensive.”

“Just as we would if they spent time at a waiting room in a medical clinic or wherever, we try to understand who was there who might have been exposed and is there anyone who needs follow up,” she said.

Those who have carried the measles in Santa Clara county have not infected other people so far, Cody added.

“We are extraordinarily fortunate in our county that our vaccination rates are very high so it’s unusual to see the spread of illness,” she said.

However, the outbreak has caused concern for those who are not vaccinated, such as children.

News of the exposure comes as communities in the Bay Area and across the country grapple with measles outbreaks. Earlier in April, officials at the University of California, Davis Medical Center in Sacramento warned 200 people that they may have been exposed to measles in March.

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So far this year, there have been eight other cases, including in Santa Cruz and San Francisco.

Officials with the San Francisco Department of Public Health on April 9th issued a notification regarding possible measles exposure from a contagious person who spent time in the city during the first few days of the month.

Last month, Santa Clara County health officials issued three separate alerts on potential measles exposures, including from a tourist who possibly exposed thousands of people by visiting multiple landmarks, restaurants and malls.

Also last month, Alameda County health officials warned patrons of a barbecue restaurant in Livermore of being possibly exposed to the disease.

According to the CDC, just this year, there have been over 500 measles cases within the U.S. In California alone, there have been over 20 cases reported.

“I’m surprised about the entire thing,” said one Mountain View man who didn’t want to release his name. “Not vaccinated by choice, they’re putting everybody else in the world at risk.”

Dr. Cody said the investigative work they do after a measles case surfaces is largely for prevention, and to alert parents with children who have not yet been vaccinated.

“We’re really doing this to protect the people who can’t be vaccinated,” she said. “Measles is one of those that is unusual because we don’t see it everyday.”

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Cody would not confirm if the person infected was a Google employee. Google did not respond to our requests for a comment.