BLOOMINGTON, MN — A child with a confirmed case of measles was infectious while visiting the indoor theme park at the Mall of America on May 24, according to the Minnesota Department of Health (MDH).

Anyone who was at the MOA between 5 p.m. and 9 p.m. that day may have been exposed, health officials said Monday. Symptoms of measles could appear between May 31 and June 14. Unvaccinated individuals, or those who have never had measles, are most at risk and should monitor for signs of infection.

The child, who is from Dakota County and is unvaccinated, has not traveled outside Minnesota recently and had no known exposure to measles, MDH said. Officials called the case concerning because the source of the infection is unknown.