The Texas health department reported 561 cases of measles in the state on Tuesday, an increase of 20 from April 11, as the United States battles an outbreak of the childhood disease that began in the West Texas area.

The total measles cases in Texas increased by 20 since Friday to 561 since late January, which leads the nation by a wide margin, the Texas Department of State Health Services announced Tuesday.

State health officials on Tuesday said the number of measles cases in the state linked to a West Texas outbreak has grown to 561 since January.