Frank Wagner Elementary School in Monroe now has one confirmed mumps case and one probable case, putting the statewide outbreak at 694 — 42 of those in Snohomish County.

Monroe School District marketing liaison Erin Zacharda said the two ill students were in the same class. As of Monday, 20 phone calls were made to the parents of children who haven't shown proof of immunity to the disease; all were asked to stay home. Four were later able to provide documentation required to return to class, she said.

“We are concerned about anything that affects the health of our students, but the fact that no new probable cases have been reported is very reassuring,” Zacharda said.

The decision to exclude students is under the authority of Snohomish County Health District health director Dr. Gary Goldbaum. The policy includes anyone who can't prove immunity “by age, disease history, antibody testing, or vaccination documentation,” in schools with one or more confirmed case or two or more probable cases.

The recess lasts 26 days after the salivary glands in the cheeks, or parotid gland, becomes swollen in the most recent case someone was likely exposed to. Enlarged glands are one of most notable symptoms of mumps.

Most cases are not severe, but can occasionally lead to hearing loss or meningitis — the swelling of the brain or spinal cord. Fever, fatigue, loss of appetite and aches are also common, though no symptoms are also possible. The testicles in boys who have hit puberty can also be a sign of contraction.

The outbreak has yielded some of the highest numbers Washington has seen since the 1970s. In recent years, the amount of reported cases has fallen well below triple digits.

The Washington State Department of Health recommends vaccination as the best protection against spreading mumps. It isn't a guaranteed barrier, but about 88 percent of those who do receive the full two-dose MMR (measles, mumps and rubella) vaccine will never get sick. Those who do will likely have fewer or less severe symptoms.

More than 85 percent of Snohomish County's students met all immunization requirements for their age during the 2015-16 school year, according to the department of health.

Snohomish County Health District public and government affairs manager Heather Thomas said in addition to the mumps cases, the agency has responded to a number of other outbreaks in Snohomish County, including pertussis (whooping cough) and the flu. Staff has been strained under the volume, she said.

Interviews with family members and conversations with medical providers are scheduled once a confirmed or probable case is reported, Thomas said. Labs are contacted for testing information, and there are numerous follow-ups with school nurses and administrators, and “this is just for mumps,” she said. 

Thomas said the county seems to be experiencing the same trend seen statewide in terms of the number of confirmed and probable cases cropping up this year. She said anyone who thinks they have the mumps should stay home and call their health care provider. Use common hygiene practices, and make sure vaccines are complete and up to date. Don't share eating utensils or food, and avoid contact with anyone who has contracted the illness, she said.

Zacharda said the schools are following those guidelines laid out by the health district in response to the confirmed and probable cases. Park Place Middle School still had one confirmed case and one probable case as of Wednesday, March 29.

The department of health updates its list of confirmed and probable cases every Thursday. Cases in Snohomish County can be tracked at snohd.org/mumps.