To: Health Care Providers, Hospitals, Ambulatory Care Centers, College Health Services
From: Susan Schoenfeld, Deputy State Epidemiologist
Date: March 17, 2010
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The State University of New York at Plattsburgh is experiencing an outbreak of mumps.
Three cases have been confirmed to date, with others under investigation. The Centers for Disease Control & Prevention (CDC), along with public health officials in the Northeast states and Quebec, are involved with an ongoing investigation of a multi-state mumps outbreak as well as several clusters of mumps disease. This outbreak was first noted in the summer of 2009 among tradition-observant Jewish communities in New York and New Jersey. Despite control efforts, the outbreak continues. There is no known epidemiological link between this outbreak and the cases in Plattsburgh. No cases have been reported in Vermont.
- The best way to minimize risk of mumps is to ensure that all children and adults are up to date with measles-mumps-rubella (MMR) vaccine. Mumps vaccine should be given as MMR or MMRV routinely to children at 12-15 months of age, with a second dose of MMR typically administered at 4-6 years of age. For older individuals, adequate immunization is two doses of mumps containing vaccine for school-aged children and adults at high-risk (health care professionals and students at post high-school educational institutions) and a single dose for other adults born in or after 1957.
- Studies have shown that a single dose of MMR vaccine is 80 percent effective (range 64%-95%), while two doses are approximately 90 percent effective (range 88%-95%) in preventing disease. Mumps may occur in fully vaccinated people.
- Consider mumps in the differential diagnosis of patients presenting with compatible clinical and epidemiological features.
- Report suspected cases of mumps to the Vermont Department of Health Infectious Disease section by calling 802-863-7240 or 1-800-640-4374 (within Vermont only). An epidemiologist is also available after regular working hours.
Early symptoms of mumps are non-specific, and include myalgia, lack of appetite, malaise, headache, and low-grade fever. Parotitis is the most common manifestation and this occurs in 30 to 40 percent of people who are infected. Parotitis may be unilateral or bilateral, and any combination of single or multiple salivary glands may be affected. Parotitis tends to occur within the first two days of illness, and may first be noted as earache and tenderness on palpation of the angle of the jaw. Symptoms tend to decrease after one week. Symptoms usually start 16 to 18 days after a person has been exposed to the mumps virus, but can start anywhere from 12 to 25 days after exposure. As many as 20 percent of mumps infections are asymptomatic, and 40 to 50 percent may have non-specific or only respiratory symptoms.
Unless there is a known epidemiologic link, mumps is an uncommon infection and parotitis has other etiologies. For patients with parotitis lasting two days or more and who meet the clinical case definition and epidemiologic criteria described below, contact the Infectious Disease section (863-7240). Under certain circumstances, with prior arrangement, specimens for serology and virus detection may be submitted through the Vermont Department of Health Laboratory to be sent to CDC for diagnostic testing.
• Clinical case definition: Acute onset of unilateral or bilateral tender, self-limited swelling of the parotid or other salivary gland, lasting two or more days, and without other apparent cause.
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• Epidemiologic criteria: Travel to an area experiencing mumps and/or direct contact with a person with known or suspected mumps.
Less strict epidemiologic criteria may be considered for unvaccinated individuals.
Laboratory Testing is recommended when there is a suspicion that a patient may have mumps. The type of testing recommended varies depending on immunization history and illness history.
Virus Detection: Particularly among previously immunized suspected cases, mumps virus detection is an important method of case confirmation.Buccal swabs samples can be tested for the presence of mumps virus (growth in culture) or mumps viral RNA using standard reverse transcriptase-polymerase chain-reaction (RT-PCR) methods. Buccal samples have the best chance of containing virus when collected on day one to three after onset of parotitis.
Serology: IgM antibodies usually become detectable within three to four days of clinical illness, and reach a peak about one to two weeks after onset. However, IgM may be transient or missing in people who have had one or more doses of mumps-containing vaccine. As a result, a negative IgM does not rule out mumps. Sera should be collected within three to four days of symptom onset for IgM testing or as the acute specimen for possible seroconversion of IgG antibody. Convalescent sera should be drawn two weeks later.
Serum for IgM and viral specimens should be handled as per facility routine. Mumps virus immune status (IgG) testing can also be performed by the Health Department Laboratory to determine immune status in asymptomatic persons. Laboratory specimens must be accompanied by a Clinical Test Request Form (Micro 220). http://healthvermont.gov/enviro/ph_lab/documents/VDHclinical_form.pdf