LITTLE ROCK — The Arkansas Department of Health said Wednesday it has identified a “limited number” of mumps cases in Pulaski County.

Since late August, the mumps outbreak in Arkansas has involved 769 people, many of them in Northwest Arkansas. As of Wednesday no Pulaski Schools had been affected, the Health Department said.

The agency said it urges Arkansas residents to make sure they and their loved ones are up to date on their mumps, measles and rubella, or MMR, vaccinations and practice infection control by washing their hands regularly and staying home if they suspect they are sick.

“We are very concerned about this outbreak,” Dr. Dirk Haselow, state epidemiologist and outbreak response medical director for the Health Department, said in a news release. “Mumps can have serious complications. We continue to see a high number of new cases.”

Mumps is a viral illness that is transmitted by direct contact with respiratory droplets or saliva from an infected person. It is best known for painful, swollen salivary glands that show up as puffy cheeks and swollen jaw. Boys may also have painful, swollen testicles. In some of these cases, fertility can be affected.

Other symptoms include fever, headache, muscles aches, tiredness, and loss of appetite. There is no treatment, and symptoms usually resolve themselves within a few weeks. Mumps is usually a mild disease in children, but in adults it may be more serious disease and involve complications such as deafness or encephalitis, an inflammation of the brain.

The MMR vaccine is a live virus vaccine and is not recommended for pregnant women or patients with a weakened immune system. Adults born before 1957 are generally considered to be immune to mumps and do not need to receive the MMR vaccine.