Thirty babies have been placed under home isolation in Alameda County after possible exposure to measles linked to a holiday outbreak at Disneyland last month.
Officials with the Alameda County Public Health Department asked the parents of the infants to keep their children at home to avoid further exposure to the contagious illness, department spokeswoman Sherri Willis said.
The babies are not infected, Willis said, but had some contact or connection to the measles patients in Alameda County.
"It is our job to try to determine who has been exposed," Willis said.
There are five confirmed measles cases in Alameda Count, four of which were linked to Disneyland.
The measles outbreak in California began after several people were exposed to the disease while visiting Disneyland between Dec. 17 and 20. There are now 87 confirmed cases in seven states and Mexico as the outbreak centered in California continues to spread.
Public health officials have contacted 500 people in Alameda County who were possibly connected to the measles patients.
"Measles is in the community," Willis said. "You don't have to be connected."
Officials said the risk of contracting measles is rapidly spreading.
In Santa Clara County, hundreds of people are at risk of contacting the diseases after officials confirmed they had two new cases.
Officials issued a warning to Bay Area residents after two people infected with measles visited several public shopping centers last week.
One of the two infected patients visited a Costco and Wal-Mart in Gilroy from 4 p.m. to 6 p.m. on Jan. 18.
The next day, the same person went to a Dave & Buster's in Milpitas from 6 p.m. to 9 p.m. Public health officials tried to reassure residents that the patient did not walk through the mall, where the restaurant is located.
Officials said the risk of developing the highly infectious respiratory illness is low, especially if any encounter with a measles patient is brief.
Still, public health officials said they are working with the businesses to inform employees and customers to check their vaccination records.
People who have not been vaccinated and were exposed to measles are at higher risk of developing an infection.