Michigan has its second measles outbreak of the year, health officials reported.

Grand Traverse County in northern Michigan confirmed an outbreak of three cases Tuesday.

The state declared an earlier outbreak of four cases in Montcalm County, near Grand Rapids in western Michigan, over June 2. The state has had 16 cases total in 2025.

The CDC defines a measles outbreak as three or more cases that have a confirmed connection to each other. It is considered over when six weeks have passed without a new case in that specific outbreak; it does not mean all measles cases have ended in the state. Health officials in late May and early June reported two cases in Marquette County and one in Ontonagon County, the first found so far in the Upper Peninsula.

There have been 1,227 confirmed measles cases in the United States this year, the Centers for Disease Control and Prevention said Wednesday.

There are three other major outbreaks in North America. The longest, in Ontario, Canada, has resulted in 2,212 cases from mid-October through June 24. The province logged its first death June 5 in a baby who got congenital measles but also had other preexisting conditions.

Another outbreak in Alberta, Canada, has sickened 1,122 as of Friday. And the Mexican state of Chihuahua had 2,485 measles cases and eight deaths as of Thursday, according to data from the state health ministry.

Other U.S. states with active outbreaks — which the CDC defines as three or more related cases — include Arizona, Colorado, Georgia, Illinois, Iowa, Kansas, Montana, North Dakota and Oklahoma.

In the U.S., two elementary school-aged children in the epicenter in West Texas and an adult in New Mexico have died of measles this year. All were unvaccinated.

Measles is caused by a highly contagious virus that’s airborne and spreads easily when an infected person breathes, sneezes or coughs. It is preventable through vaccines and has been considered eliminated from the U.S. since 2000.