According to the Detroit Free Press, the number of measles cases in Michigan has reached 41, including the first reported in Washtenaw County.

The Michigan Department of Health and Human Services updated the number Monday with two additional cases.  Thirty nine cases have been confirmed in Oakland County.

Authorities are trying to determine possible exposure sites in Washtenaw County in southeastern Michigan.  They're also urging people again to get vaccinated if they haven't received the vaccine in the past.

Measles is highly contagious and is spread by personal contact and through the air.  The state considers the vaccine to be highly effective and safe.  A single dose protects about 95 percent of children.  After two doses, almost 100 percent are immune.