Four young people from the Milwaukee area, including three children from the same daycare, have been diagnosed with the highly contagious illness. A 37-year-old adult has also been diagnosed with measles.
The health department is now holding special clinics to provide the public with measles vaccines. And 12 children who attended the Kingdom Care daycare are now being quarantined at their homes to make sure they don't have the disease.
No one is sure what spurred the outbreak. But doctors say even people who have been previously vaccinated should be on notice because a vaccine's protection can fail over time.