The Oklahoma State Department of Health reported that a person now living in Oklahoma that recently traveled abroad has been diagnosed with the state’s first case of measles since 1997.

The person diagnosed is the spouse of an Oklahoma State University student who lives off campus. The age and sex of the person has not been released, nor has the country he or she visited, according to Tulsa World.

Measles, a highly contagious respiratory disease, was considered to be eliminated from the United States in 2000. But according to the Centers for Disease Control and Prevention, there has been an increased number of cases in recent years.

After being exposed to measles, symptoms typically start to develop between seven to 18 days after. Symptoms typically begin with a fever, red eyes, runny nose and cough. A few days later a rash appears, usually on the face, and then moves down the body.

The increase is said to have possibly been because of a growth in international travel as well as the movements in the U.S. against vaccinations.

In Oklahoma, the vaccine for measles, called MMR, is required before a child starts school. But there are exemptions granted for personal, religious or medical reasons. The exemption rate for kindergartners in Oklahoma is 1.4%, according to the state Health Department.

Kristy Bradley, a state epidemiologist, says that the case is not connected with the recent California outbreak that started in December last year that ended up affecting 150 people in seven states. Although it is also not a shock that the disease showed up in Oklahoma, given the recent increase in cases in the U.S. overall.

In Oklahoma in 2013, the rate of children 19 to 35 months who had received the measles vaccine was 89.8 percent, according to the department.

There is a commercially available test for people who are not sure whether they have received the vaccine, but there is also no harm in getting the vaccine more than once if a person is unsure. The vaccine can also be given immediately after exposure and still be effective.

The state Health Department released a list of Stillwater locations, including several restaurants and two grocery stores, where people could have been exposed to the virus from March 13 to March 19.

OSU officials said they are working with state and local health department staff who are trying to determine the exact source.