SPRINGDALE, Ark. — Arkansas’ biggest cluster of mumps cases in more than five years has been confirmed in the northwest part of the state, and unvaccinated students at affected schools are being asked to stay home until the outbreak ends.

There are two confirmed cases and 18 suspected cases of mumps in the Springdale area, which is the largest cluster since 2010, the Arkansas Department of Health said Wednesday.

The outbreak currently affects four schools in the Springdale School District. Health Department spokeswoman Meg Mirivel said that unvaccinated students who attend a school with a confirmed case of mumps must stay home for 26 calendar days — the maximum incubation period for mumps — from the point of exposure.

Mirivel said those afflicted include both vaccinated and unvaccinated people.

Mumps is a viral infection that causes swelling in the salivary glands and cheeks. Those with the illness may also have headaches, fatigue, muscle aches and low-grade fevers.

“Mumps is easily spread from person to person,” state epidemiologist Dr. Dirk Haselow said. “We expect to see more cases in the coming weeks. We urge Arkansans to make sure that they and their loved ones are up-to-date on the MMR (measles, mumps and rubella) vaccine.”