The Texas health department reported 259 measles cases in the state on Friday, an increase of 36 cases from its previous count on March 11, as one of the largest outbreaks the U.S. has seen in the last decade spreads.

In what could become a spiraling health crisis for the state, public health officials in Lamar County on Thursday announced four confirmed cases of measles. Paris-Lamar County Health District officials said the extremely contagious virus had been diagnosed in four patients who range in age from 5 months to adulthood.