A measles outbreak that started in Portland has spread into Washington state.
Officials are calling it a state of emergency.
Measles was declared eliminated in the U.S. in 2000 but has made a comeback because adults aren’t vaccinating their children.
Kelsey Seybold's Dr. Melanie Mouzoon said this is a concern for parents whose children are too young to be immunized (under the age of one).
She said she expects it to spread throughout Washington state very quickly.
Washington state health officials have warned that people infected with the disease had visited schools, churches, a dentist's office, a Costco store, an Ikea store and the Portland airport.
"Measles is so contagious that if a person is in an airport waiting room two hours after someone with measles has passed through, they can still catch measles from the droplets in the air. It's that contagious," said Mouzzon.
Washington state health officials added the outbreak could still be in its infancy as the incubation period of the virus averages 14 days. Those infected can spread measles to others four days before and four days after the rash appears.
Mouzoon said Northwest US is an area with a lot of unvaccinated children.
"Central and South America actually have pretty good immunization rates against measles. It's wealthy, American, unvaccinated travelers that are bringing this illness over," said Mouzzon.
She said if you've chosen to not vaccinate your children, you shouldn't travel to places where there are measles outbreaks, like Europe and the Phillipines.
The highly contagious disease can be deadly.
In November, the World Health Organization warned that measles cases worldwide had jumped more than 30 percent in 2017 compared to 2016, partly because of children not being vaccinated.