Ontario's chief medical officer of health says six infants have been born with congenital measles since an outbreak began last fall, adding they were infected in the womb through mothers who were not vaccinated.

Thousands of people, mostly children, in the U.S., Canada, and Mexico have contracted the vaccine-preventable disease this year.

An infant infected with measles has died in southwestern Ontario, Canada, the province's chief medical officer of health said in a statement on Thursday. "An infant, born prematurely and infected with measles,