An unvaccinated adult who lives in Pueblo developed measles after visiting a part of Mexico that has an ongoing outbreak.

The state health department has identified the South Side Walmart as a possible measles exposure site. Here's what to know.

The measles outbreak in western Texas is continuing to grow with a total of 422, according to new data published Tuesday.

Texas and New Mexico health departments said on Friday that the number of measles cases in their states rose 20% since their last reports three days ago, as experts warn they expect the outbreak to further spread in coming weeks.

Twenty-three measles cases have been reported in Kansas, and the state health department said they could be linked to an ongoing outbreak that has infected at least 379 people across Texas, New Mexico and Oklahoma.

Texas has reached 400 cases of measles in an outbreak that started two months ago. Texas, New Mexico, Ohio, Kansas and Oklahoma all have active measles outbreaks.

Texas and New Mexico's health departments said on Friday measles cases in their states have risen to 444, an increase of 74 infections since their last reports three days ago, as the U.S. deals with one of the largest measles outbreaks in a decade.

Dr. Rachel Herlihy, state epidemiologist for the Colorado Department of Public Health and Environment, states, “Measles is actually the most transmissible infectious disease that we know of. It's much more infectious than other infectious diseases that we see more commonly and have come to know over the last couple of years.