Here’s what to know about the current measles outbreak, how common the measles is in the U.S., how it spreads and what the symptoms and treatment are.

Measles is highly contagious and can spread from one person to nine out of 10 people close to them, according to the CDC, which notes a person infected with measles can spread it to others four days before through four days after the rash appears. Measles can spread through coughing, sneezing and infected surfaces.

An unvaccinated New Mexico adult who tested positive for measles has died, the second death in a growing outbreak centered along the Texas-New Mexico border, officials said Thursday. The individual did not seek medical care before death,