ToplineThere was a slight uptick in measles cases in the U.S. over the last week, according to Centers for Disease Control and Prevention, as outbreaks of the highly contagious illness spread in Texas and dozens of other states.

The measles outbreak centered in northwest Texas grew to 728 cases on Friday, a net gain of 10 new infections over the past week, according to the latest update from the Texas Department of State Health Services.

Texas added just 10 new cases this week, but there must be no new cases over a 42-day period before an outbreak is declared over.