Health Alert
DPH INVESTIGATING MUMPS OUTBREAK ASSOCIATED WITH FEBRUARY 10, 2018 BAILE MEXICANO DANCE AT CHASE CENTER, WILMINGTON

Summary

The Delaware Division of Public Health (DPH) is issuing this health advisory to alert health care providers of an outbreak of mumps in New Castle County and to provide guidance on mumps clinical features, laboratory testing, prevention, and reporting. DPH urges providers to:

1. Report patients with a clinical picture compatible with mumps to DPH as soon as possible and without waiting for the return of laboratory results.
2. Offer MMR vaccination to persons who report attending the Baile Mexicano dance that was held at the Chase Center on the Riverfront in Wilmington on February 10, 2018, as long as there are no contraindications. Those who are not up to date on MMR vaccination should be brought up to date. Also consider offering a third dose to those who are up to date.
3. Offer MMR vaccination to household contacts of persons with confirmed mumps as long as there are no contraindications to vaccination. This includes those who are not up to date on their mumps vaccinations as well as those who are up to date (to whom a third dose of MMR should be offered).

Background

As of March 20, 2018, there are three known cases of mumps (one confirmed and two probable cases) with a fourth case being investigated. The three cases identified so far are all known to have attended a social dance (Baile Mexicano or Mexican Dance) that took place at the Chase Center on the Riverfront in Wilmington on February 10, 2018. DPH is sharing information about mumps with health care providers to help identify others who may have been exposed to mumps at this event. The Centers for Disease Control and Prevention (CDC) notes that a substantial increase in the number of mumps outbreaks and outbreak-associated cases have occurred in the United States since late 2015.

Clinical manifestations

Mumps is an acute viral infection characterized by a non-specific prodrome including myalgia, anorexia, malaise, headache, and fever, followed by acute onset of unilateral or bilateral tender swelling of parotid or other salivary glands. Mumps infection may on occasion present with only respiratory symptoms, or may be asymptomatic. Previously vaccinated persons are less likely to present with severe symptoms or complications than under-vaccinated or unvaccinated persons.

Complications of mumps infection can include deafness, orchitis, oophoritis meningitis and encephalitis. Complications of mumps tend to occur more frequently among adults than children. According to the CDC, death from mumps is exceedingly rare.

Transmission

Transmission of mumps virus occurs by direct contact with respiratory droplets, saliva, or contact with contaminated fomites. The incubation period is generally 16 to18 days (ranging from 12 to 25 days) from exposure to onset of symptoms. Mumps is most infectious from two days before, to five days after, symptom onset but asymptomatic people can transmit the disease.

Diagnosis

Laboratory testing for mumps may be done by testing blood specimens sent for serology and by polymerase chain reaction (PCR) testing of buccal swabs. Urine is a less reliable specimen for testing, but is an option.

For serology testing, acute phase serum should be obtained as soon as possible and convalescent serum should be obtained two to three weeks later. Buccal swabs for PCR testing are collected by massaging the parotid gland prior to swabbing the area around the Stensen's duct. Swabs should be collected using synthetic swabs; not with cotton swabs. A video from the CDC on how to collect buccal samples is listed under "Additional Information." Information on how to transport specimens is also listed under "Additional Information."

Note that in patients with a compatible clinical syndrome and in the right epidemiologic context (attendance at the Baile Mexicano dance or contact with persons who attended the dance), mumps should not be ruled out on the basis of negative laboratory results. Serologic tests should be interpreted with caution particularly in those previously vaccinated against mumps, as false negative IgM results (negative IgM in person with mumps) may occur.

Prevention

The principal strategy to prevent mumps is to achieve and maintain high immunization levels. Mumps can be prevented with the MMR vaccine. This protects against three diseases: measles, mumps, and rubella. The CDC recommends children get two doses of MMR vaccine, starting with the first dose at 12 to 15 months of age, and the second dose at four to six years. Teens and adults who did not get the recommended MMR vaccines per the above schedule should be vaccinated so they are up-to-date.

During mumps outbreaks, the Advisory Committee on Immunization Practices recommends that persons previously vaccinated with two doses of a mumps virus-containing vaccine (MMR or MMRV) who are identified by public health authorities as being part of a group or population at increased risk for acquiring mumps because of an outbreak should receive a third dose of a mumps virus-containing vaccine to improve protection against mumps disease and related complications.

As such, DPH is recommending that patients who identify as having attended the Baile Mexicano dance at the Chase Center on the Riverfront in Wilmington, on February 10, 2018, be offered a dose of MMR. In addition, household contacts of persons diagnosed with mumps should be vaccinated with MMR regardless of whether or not these household contacts are up to date on their vaccines.

Those patients who attended the Baile Mexicano or are household contacts of persons with mumps and who do not have health insurance or whose insurance does not cover MMR, should call the DPH's New Castle County location at the Hudson State Service Center Immunization Clinic at 302-283-7587, (and select option #2), for an appointment to get an MMR vaccine. Patients who live in Kent County and need vaccination may call DPH's Kent County Immunization Clinic at 302-857-5140 and those in Sussex County may call DPH's Georgetown Immunization Clinic at 302-515-3220

Patients suspected of having mumps should be instructed to self-isolate at home for five days after symptom onset and should be advised to stay away from work and school.

Reporting

Mumps is a rapidly reportable disease in Delaware. Suspected cases of mumps should be reported to DPH via fax at 302-223-1540; email at reportdisease@delaware.gov; or phone, 302-744-4990. Do not wait for laboratory test results to return before reporting.

Additional Information

1. Video on collection of buccal swab https://www.youtube.com/watch?v=ThvoJBjsUvQ
2. Specimen transport https://www.cdc.gov/mumps/lab/specimen-collect.html
3. CDC information for providers https://www.cdc.gov/mumps/hcp.html
4. Guidance on administration of third dose of MMR during outbreaks https://www.cdc.gov/mmwr/volumes/67/wr/mm6701a7.htm

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