Clinician Update: Mumps Outbreaks in Oregon

December 21, 2016

Four cases of mumps have been confirmed in Washington County, and more cases may present for evaluation in the coming weeks as mumps outbreaks are ongoing in Oregon and elsewhere in the U.S. The majority of mumps cases in recent years have been in fully vaccinated individuals. The four Washington County cases have been in fully vaccinated school-age children who attend the same school.

We ask for assistance from providers to identify additional  cases to help track further spread. If you see a patient with salivary gland swelling:

  • Include mumps in your differential diagnosis, even if the patient is fully vaccinated.
  • Minimize exposure to other patients and use droplet and standard precautions.
  • In patients with a history of MMR vaccination, the preferred test for diagnosis is mumps PCR.
  • If 3 days or less since onset of symptoms, obtain a buccal swab for testing.
  • If more than 3 days since onset, obtain both a buccal swab and a urine sample for PCR testing.
  • In unvaccinated patients, performing both mumps IgM serology and mumps PCR can increase the chances of detection.
  • If mumps is suspected, then request that the patient be isolated at home for 5 days from the onset of parotitis.
  • Report suspected mumps cases to the county public health department of their residence.
  • Commercial laboratories perform mumps PCR testing. Testing through the public health laboratory is approved on a case-by-case basis through the county public health department

Most persons with mumps present with salivary gland swelling, usually parotitis. Prodromal symptoms may include low-grade fever, myalgia, anorexia, malaise, and headache. Some persons may be asymptomatic or have only nonspecific or respiratory symptoms. Complications are infrequent but include orchitis, oophoritis, and aseptic meningitis. Mumps is spread through close contact with respiratory secretions, and infected persons are most infectious 2 days before and 5 days after onset of parotitis. The incubation period of mumps is 12–25 days (average 16-18 days).

CDC information on mumps:

CDC information on mumps outbreaks in the U.S.:

Clackamas County Public Health: 503-655-8411
Multnomah County Public Health: 503-988-3406      
Washington County Public Health: 503-846-3594