There are now three confirmed cases of measles in Colorado. All investigations are ongoing and are typically handled at the county level with support from the state.

Colorado health officials warned Tuesday that measles may be spreading undetected in Colorado following the confirmation of the state’s third case this year in an Archuleta County resident. The Colorado Department of Public Health and Environment’s warning comes after two previous measles cases in Pueblo and Denver.

A Pueblo resident was exposed to a measles outbreak in Mexico during travel and tested positive for the disease. Here's everything you need to know.