Health officials in Los Angeles are warning passengers about measles exposure after a passenger traveled through the busy Los Angeles International Airport last month.

According to USA Today, the infected passenger traveled on China Eastern Flight 583 through the airport’s Terminal B, a popular terminal for international flights, on the morning of Feb. 21

Health and safety officials said that travelers in Terminal 3 between 9 a.m. and 9 p.m. could have also been exposed because the infected person had a layover before catching Delta Flight 5705 out of gate 32.

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Terminal B is home to 29 gates made up of several international airlines including Air France, China Airlines, Lufthansa, and Korean Air.  Terminal 3 features 12 gates and is where Delta Airlines, Interjet, and Copa is situated.

L.A. County officials told USA Today reporters that they first learned about the case of the highly contagious virus on March 7.

A statement on the county’s public health website describes measles as a highly contagious viral infection that causes fever, runny nose, and a severe rash.

The virus is spread through coming in contact through a cough or sneeze of an infected person. It’s possible that exposure to measles can infect others 2 hours after the infected person has left the room.

People with measles are highly contagious and health officials say that the incubation period for developing measles is up to 21 days after being exposed to someone who has the disease.

If you think that you or someone in your family has been exposed to, or has measles, you should contact your doctor’s office right away.