Three New Zealand children infected with measles traveled through Los Angeles to Denver on Dec 11 and may have exposed other travelers to the disease.

Travelers who visited the Denver airport’s Concourse A, train to baggage claim, west baggage claim and west level 4 passenger pick-up areas between 1:15 p.m. and 5:45 p.m. on December 11 could’ve been exposed to the virus, Colorado’s Tri-County Health Department reported.

Los Angeles County health officials issued a similar warning for passengers who visited Terminals 4 and 5 between 6:50 a.m. and 12 p.m. on the same day.