In the last year, several cases of measles have been identified in the Philadelphia region; last winter, a measles outbreak sickened nine people and sent six to the hospital in Philadelphia.

Mesleas is extremely infectious, and health officials have identified several potential exposure locations across the county.

If you think you’ve been exposed to measles, do not show up at a clinic or hospital without calling first, Public Health — Seattle & King County said. To avoid possibly spreading measles, limit contact with others and wear a well-fitting mask if you need to go to a health care facility, the department said.