The measles outbreak has reached 30 states, according to new numbers recorded by the Centers of Disease Control.
The CDC reports both Ohio and Alaska have now been added to the list of states affected.
New numbers posted on July 18 report 1,148 cases have been recorded, marking an increase of 25 cases since last week.
This also marks the most cases reported in the U.S. since 1992, and since measles was declared eliminated in 2000.
Experts from the CDC say the measles rash shows up three to five days after contraction. Symptoms of the measles include high fever, cough, runny nose and watery eyes.
The CDC recommends getting the MMR vaccination, which protects patients from measles, mumps and rubella.
If you think you may have been exposed to measles, you should contact your doctor immediately.