The mumps outbreak in Washington state is on the cusp of 300 confirmed and probable cases as 291 have been reported in five counties through Wednesday.

Image/ National Atlas of the United States
Image/ National Atlas of the United States

The breakdown stands at King County (163), Spokane County (90), Pierce County (34), Snohomish County (3) and Yakima County (1).

In King County, 63.2 percent of patients report being up to date on their measles-mumps-rubella (MMR) vaccine. Roughly the same percentage has been reported as fully vaccinated in Spokane County.

According to the Centers for Disease Control and Prevention (CDC), 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. 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 adults may have more serious disease with complications.