Health officials in two US states are tracking measles outbreaks as cases rise to nearly 100 people. The Texas Department of State Health Services reported Friday that it was aware of 90 cases diagnosed in the last month in the South Plains area,

Measles is a respiratory virus that can survive in the air for up to two hours. Up to 9 out of 10 people who are susceptible will get the virus if exposed, according to the U.S. Centers for Disease Control and Prevention.

Texas reported 90 cases this week, while New Mexico reported nine. A majority of the cases have been in a Texas county where vaccination rates have lagged behind the rest of the state.