A Texas measles outbreak has doubled in the last week to 124 cases, state health officials said Tuesday, a day after they warned a person infected with the highly contagious disease had traveled from the outbreak zone.

Four of the newly reported cases are located in Dallam County, 200 miles north of Gaines County where the outbreak originated.

The surge in measles cases in Texas began in late January when two cases were reported in Gaines County, as reported by The Houston Chronicle. Since then, the number of cases in Gaines County reached 80,