Recently, a newspaper published an article stating that more than 6000 cases of Mumps have been reported from Kerala this year. This article will briefly describe the disease, as well as prevention and control measures applicable.
Background Information:
Mumps is a contagious disease that is caused by a virus. It typically starts with a few days of fever, headache, muscle aches, tiredness, and loss of appetite. Then most people will have swelling of their salivary glands (often referred to as parotitis when the parotid gland, located in front and below the ear, swells). This is what causes the puffy cheeks and a tender, swollen jaw.
Key Messages:
Mumps is a viral illness caused by a paramyxovirus.
The average incubation period for mumps is 16 to 18 days, with a range of 12 to 25 days.
Mumps usually involves pain, tenderness, and swelling in one or both parotid salivary glands (cheek and jaw area). Swelling usually peaks in 1 to 3 days and then subsides during the next week. The swollen tissue pushes the angle of the ear up and out. As swelling worsens, the angle of the jawbone below the ear is no longer visible. Often, the jawbone cannot be felt because of swelling of the parotid. One parotid may swell before the other, and in 25% of patients, only one side swells. Other salivary glands (submandibular and sublingual) under the floor of the mouth also may swell but do so less frequently (10%).
Nonspecific prodromal symptoms may precede parotitis by several days, including low-grade fever which may last 3 to 4 days, myalgia, anorexia, malaise, and headache. Parotitis usually lasts on average 5 days and most cases resolve after 10 days. Mumps infection may also present only with nonspecific or primarily respiratory symptoms, or may be asymptomatic. Reinfection after natural infection and recurrent parotitis, when parotitis on one side resolves but is followed weeks to months later by parotitis on the other side, can also occur in mumps patients.
Mumps can occur in a person who is fully vaccinated, but vaccinated patients are less likely to present severe symptoms or complications than under- or unvaccinated cases. Mumps should be suspected in all patients with parotitis or mumps complications, regardless of age, vaccination status, and travel history.
The mumps virus replicates in the upper respiratory tract and is transmitted person to person through direct contact with saliva or respiratory droplets of a person infected with mumps. The risk of spreading the virus increases the longer and the closer the contact a person has with someone who has mumps. The infectious period is considered from 2 days before to 5 days after parotitis onset, although virus has been isolated from saliva as early as 7 days prior to and up to 9 days after parotitis onset. Mumps virus has also been isolated up to 14 days in urine and semen.
When a person is ill with mumps, they should avoid contact with others from the time of diagnosis until 5 days after the onset of parotitis by staying home from work or school and staying in a separate room if possible.
Mumps complications include orchitis, oophoritis, mastitis, meningitis, encephalitis, pancreatitis, and hearing loss. Complications can occur in the absence of parotitis and occur less frequently in vaccinated patients. Some complications of mumps are known to occur more frequently among adults than children.
Orchitis (inflammation of the testes) occurs in approximately 30% of unvaccinated and 6% of vaccinated post-pubertal male mumps patients. In 60% to 83% of males with mumps orchitis, only one testis is affected. Mumps orchitis has not been linked to infertility, but may result in testicular atrophy and hypofertility.
Pancreatitis, deafness, meningitis, and encephalitis have been reported in less than 1% of cases in recent U.S. outbreaks. Cases of nephritis and myocarditis and other sequelae, including paralysis, seizures, cranial nerve palsies, and hydrocephalus, in mumps patients have been reported but are very rare. Death from mumps is exceedingly rare.
Mumps that occurs in pregnant women is generally benign and not more severe than in women who are not pregnant.
People who previously had one or two doses of MMR vaccine can still get mumps and transmit the disease. During mumps outbreaks in highly vaccinated communities, the proportion of cases that occur among people who have been vaccinated may be high. This does not mean that the vaccine is ineffective. The effectiveness of the vaccine is assessed by comparing the attack rate in people who are vaccinated with the attack rate in those who have not been vaccinated. In outbreaks of highly vaccinated populations, people who have not been vaccinated against mumps usually have a much greater mumps attack rate than those who have been fully vaccinated. Disease symptoms are generally milder and complications are less frequent in vaccinated people.
Vaccination is the best way to prevent mumps and mumps complications. This vaccine is included in the combination measles-mumps-rubella (MMR) and measles-mumps-rubella-varicella (MMRV) vaccines. Two doses of mumps vaccine are 88% (range 32% to 95%) effective at preventing the disease; one dose is 78% (range 49% to 91%) effective.
RT-PCR and viral culture are used to confirm mumps infection. Buccal swabs are most commonly used for RT-PCR testing, but urine and CSF may also be used in specific situations. IgM serology can also be used to aid in diagnosing mumps infection. A patient’s vaccination status and timing of specimen collection are important for interpreting laboratory results. A negative test result does not rule out mumps infection.
Main image courtesy: https://assets.aboutkidshealth.ca/akhassets/Mumps_MED_ILL_EN.png?RenditionID=19
Useful Links:
Link to newspaper article about mumps outbreaks in Kerala:
Link to US CDC’s Mumps Clinical Diagnosis Fact sheet:
https://www.cdc.gov/mumps/downloads/mumps-clinical-diagnosis-fact-sheet-508.pdf
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