Measles has sickened nearly 150 mostly unvaccinated people in rural West Texas, and a school-age child has died.

Texas’ health commissioner told lawmakers Monday they are still trying to determine the origin of a South Plains-Panhandle measles outbreak more than a month after the first patients reported symptoms.

Measles has sickened nearly 150 mostly unvaccinated people in rural West Texas, and a school-age child has died. The virus is spreading among Gaines County’s Mennonite community, where government mandates are not trusted.