A San Juan Island adult has been diagnosed with measles and may have exposed others to the virus at three San Juan County sites, according to the Washington State Department of Health.

Others at the following sites may have been exposed:

• Cask and Schooner: March 21 from 3:45 p.m. to midnight, March 22 from 3:45 p.m. to 1:15 a.m., March 23 from 4 p.m. to midnight, and March 24 from 2:45 p.m. to midnight.

• China Pearl (upstairs bar only): March 22 from 11:30 p.m. to 3 a.m.

• King’s Market: March 24 from 3 p.m. to 5:30 p.m.

Anybody who was at the sites on the dates listed, and who either doesn’t have immunity or is unsure about it, should contact his or her health-care provider or the San Juan County Health Department at 360-378-4474.

Anyone exposed to the virus and who has not been immunized against measles will most likely get the disease, the Health Department said. Measles is especially dangerous for children younger than 12, pregnant women and people with compromised immune systems.

Two cases of measles have been confirmed in Whatcom County in March. They were traced to an outbreak of measles in the Fraser Valley, B.C., just north of the U.S.-Canada border, according to a Whatcom County news release. The majority of the cases in British Columbia are related to a private school that has a high number of unvaccinated children.