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.

The Texas public health department reported 36 more measles cases on Friday in the outbreak that began in Gaines County.