Lynn Sutfin, public information officer for the Michigan Department of Health and Human Services, told CNN that a male individual from New York traveled to Southeast Michigan by vehicle.
"He was unknowingly contagious with the measles during his visit here. All 38 other cases of measles in Southeast Michigan can be linked to this individual," she said.
The ongoing outbreak in ultra-orthodox Jewish neighborhoods in New York began in October when, according to health officials, an unvaccinated child became infected with measles while visiting Israel.
In all, more than 500 cases of measles have been reported in New York as part of this outbreak – 332 of them since January with more than 40 new cases identified in the last week.