As new cases are reported, our maps and illustrations show the spread of the virus and how infections can run through a community.

A measles outbreak that began in northwest Texas grew to 223 cases on Tuesday, with another 30 cases reported in New Mexico, according to health officials. The latest update from the Texas Department of State Health Services includes 25 new cases since the agency’s last update on Friday.

Texas and New Mexico on Tuesday reported an increase of 28 cases of measles in the last five days, bringing the total known infections to 256 in the two states since an outbreak began in late January.