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.
The number of measles cases associated with an outbreak in Texas has increased to 159 -- an increase of 13 cases in the past five days, authorities said on Tuesday.
Health authorities warned of further spread. Most U.S. measles cases this year involved people 19 and under and those without a confirmed vaccination.