The Maricopa County Department of Public Health is warning about the possibility of a measles outbreak after a person infected with the disease visited the Valley. Health Director Dr. Bob England said he or she is an unvaccinated adult who was in the area between the area between March 29 and 31.

“The individual was in very public places, around a lot of people, so that we’re very concerned that some of those folks may not be immune,” England said, “and we may have several people right about to come down with the disease right now.”

England said measles is the most infectious disease in the world and has an incubation period of up to three weeks. Unvaccinated people who are exposed have about a 90 percent chance of contracting the disease.

The locations where people may have been exposed are Sky Habor Airport Terminal 4, from 6:30 p.m. to 10 p.m. on March 29; Church of Jesus Christ of Latter-Day Saints, Cave Creek Chapel, from 1 p.m. to 5 p.m. on March 30; Wildflower Bread Company on Hayden Road in Scottsdale, from 12 p.m. to 5 p.m. March 31; and Phoenix Sky Harbor Terminal 4 from 3 p.m. to 7 p.m. March 31.

England stressed that these locations are safe to visit now, but people who visited them during the above time frames should watch for symptoms of measles. Those symptoms start with a fever of 101 degrees or higher, red and watery eyes and runny nose. That is followed by a red, blotchy rash that moves up and down the body.

England urges anyone who thinks they might have been infected and has symptoms to contact their health care provider.