One of the states hit hardest by mumps in the past six months is Washington. Since October 2016, state health officials have reported 664 confirmed and probable cases through this week. 473 of the cases have been reported since the beginning of the year.

Mumps virus/CDC
Mumps virus/CDC

Fifteen counties in WA have had mumps cases with onset dates during the first 11 weeks of 2017: Benton, Ferry, Franklin, Grant, Island, King, Okanogan, Pend Oreille, Pierce, Skagit, Snohomish, Spokane, Stevens, Thurston and Yakima. Spokane and King Counties account for the majority of cases.

The outbreak has extended to the University of Washington (UW) in Seattle. To date,  Public Health — Seattle & King County has confirmed 20 cases of mumps at UW. More cases are expected as the outbreak across King County and Washington State continues.

Seattle has seen 25 cases as of Friday.

The reported cases of mumps have been found in a small number of fraternities and sororities near the UW Seattle campus. The number of mumps cases and impacted houses changes daily as suspected cases emerge and are confirmed (or ruled out) by Public Health — Seattle & King County.

LISTEN: Jason Tetro explains the reason behind the mumps “comeback”

The mumps virus is found in saliva and respiratory droplets. It is spread from person to person through coughing, sneezing, and coming into contact with a person’s saliva by sharing drinks or utensils, food or water bottles, or by kissing. A major factor contributing to outbreaks is being in a crowded environment, such as attending the same class, playing on the same sports team or living in a dormitory with a person who has the mumps.

Symptoms include swelling and pain in one or more salivary glands (sides of the cheeks and jaw), fever, headache, muscle aches and pains, fatigue and loss of appetite. These symptoms can last up to 10 days.

Complications from mumps infection can include encephalitis (infection in the brain), meningitis (infection in the lining of the brain), painful swelling of the testicles or the ovaries, pancreatitis and hearing loss. Pregnant women who become infected with mumps during the first three months of pregnancy are at risk of miscarriage.