The Texas Department of State Health Services on Friday, reported 597 measles cases in the state since late January, an increase of 36 since the update on Tuesday. The department said the outbreak is primarily in West Texas and added that 4% or fewer than 30 of the confirmed cases are estimated to be actively infectious since their rash onset date was less than a week ago.

Texas health officials reported 36 new measles cases Friday, bringing the total number of confirmed cases since late January to 597. The state’s public health department estimates that fewer than 30 of the confirmed cases — about 4% — are “actively infectious.