A mumps infection is usually recognised by the swollen cheeks caused by inflamed parotid salivary glands. About one third of cases of mumps cases are asymptomatic, i.e. presenting with no symptoms.
Occasionally, mumps infection in the absence of telltale facial swelling only becomes apparent because of complications.
Mumps is caused by the mumps virus. There is only one strain of the virus, which circulates all around the world. As it is a human virus, it can only be spread from one person to another.
People are infectious for about a week before and after they develop symptoms of mumps. The virus is shed in saliva from the infected salivary glands and in the urine.
Infection usually occurs by contact with infected saliva, either directly (for example by kissing), or indirectly, by airborne droplets. Droplets of saliva generated by sneezing or speech can be inhaled by a nearby person.
Mumps virus most often infects children between five and nine years old. However, a number of people reach adulthood without having had the infection. Mumps infections tend to peak in winter or spring every two to five years. In countries that have vaccination campaigns, mumps has become quite rare. This is however, not the case in South Africa since the measles, mumps, rubella vaccine (MMR) is only available through the private sector.
Early symptoms of mumps may be a mild fever and a general feeling of being unwell. Swelling and pain in the salivary glands are specific symptoms that soon develop.
The parotid glands lie in the cheeks over the lower jaw on either side of the face.
The inflammation of the parotid glands
(parotitis) caused by mumps may be on one side only, but it usually affects both sides.
Other salivary glands such as the sub mandibular glands – which lie below the lower jaw – are sometimes also involved. Mumps parotitis or facial swelling causes discomfort during talking or eating.
Complications of mumps
Mumps can have a number of complications, which include the following:
1. Viral meningitis
The most common complication is viral meningitis, an inflammation of the membranes (meninges) surrounding the brain and spinal cord. It affects one in 10 people with mumps. Symptoms of meningitis are headache, stiff neck, fever, avoidance of bright light (due to the pain it causes to the eyes), nausea and vomiting.
It is not unusual in up to 50% of cases of mumps to have mumps meningitis without any sign of facial swelling, which indicates the mild nature of the condition. Unlike bacterial meningitis, viral meningitis rarely has any serious consequences.
Encephalitis is a more serious consequence of mumps and is fortunately rarer. It affects boys more often than girls. Where meningitis is an inflammation of the membranes of the brain, encephalitis is an inflammation of the brain.
It can cause flu-like symptoms such as a fever or severe headache. Encephalitis can also cause confused thinking, seizures or problems with movement or the senses.
Most people recover from mumps encephalitis, but one possible consequence is deafness, usually affecting one ear only. Encephalitis can very rarely progress to coma and to death.
3. Inflammation of the testes
Inflammation of the testes (orchitis) is another well-known complication of mumps. Orchitis usually occurs in one in four individuals who get mumps when they are past puberty. Symptoms of orchitis are testicular swelling and pain, usually involving one testis only. The testis or testes may shrink while healing, but sterility is rare.
4. Inflammation of the ovaries
A less well-known complication in post-pubertal girls and women is inflammation of the ovaries, which can cause pain and tenderness in the lower abdomen. Girls and women are more often aware of inflammation of breast tissue, which also causes pain and is is tender to the touch.
5. Temporary arthritis
Temporary arthritis is a rare complication of mumps that tends to occur in post-pubertal boys and men. This causes aching, possible redness and swelling of one or more joints.
6. Inflammation of the pancreas
Inflammation of the pancreas (mumps pancreatitis) is a fairly rare, but potentially serious complication of mumps, affecting four in 100 people. This causes quite severe abdominal pain penetrating to the back. In very rare cases, mumps pancreatitis can result in diabetes.
Miscarriage may result in a quarter of cases of women who have mumps in their first trimester of pregnancy (up to 12 weeks). However, babies born to women who have had mumps during pregnancy have no increased risk of physical or mental abnormality.
Risk factors for mumps
Anyone who has not been naturally infected or vaccinated is at risk of mumps in their lifetime. Fairly close contact with someone in the week before or after they develop the symptoms of mumps puts you at risk. As mentioned above, older teenagers and adults are at increased risk for certain of the complications of mumps. It is extremely rare to have a second infection with mumps.
A laboratory diagnosis is not usually necessary for mumps because it’s easy to recognize a person with mumps in his or her appearance.
It is possible to confirm mumps infection by looking for antibodies in the blood. If features suggesting meningitis are present, then a lumbar puncture would usually be performed to exclude other causes.
(It is important to check that the meningitis is not the more serious bacterial type.)
The mumps virus can be cultured from the spinal fluid.
- If someone has an uncomplicated mumps infection, you only need to keep the person as comfortable as possible.
- Soft or liquidised foods will help, and ice cream is likely to be appreciated!
- As with all viral infections, bed rest is advisable while there is a fever.
- In general, do not use aspirin-based drugs for children with a viral infection. Suitable painkillers include paracetamol, mefenamic acid and Ibuprofen (Brufen or Neurofen).
- Children are usually advised to stay at home for five days after the onset of symptoms.
There is no drug that works against the mumps virus.
All treatments for complications of mumps act to reduce particular symptoms, but do not affect the virus itself.
Get advice from a health professional about treating common complications such as orchitis or arthritis; an anti-inflammatory drug is likely to be prescribed.
Vaccination is the only way to avoid mumps or its complications. The mumps vaccine is usually available as part of the combined measles/mumps/rubella (MMR) vaccine and is widely used in the private health sector.
The recommended age for this vaccination is 15 months.
The South African state health service does not provide the combined vaccine as there are currently more serious vaccination priorities (measles vaccine is given singly).
The MMR vaccine is safe for most people. However, you should avoid having an MMR vaccine if you:
- Have severe immune impairment (the vaccine can be given to children with HIV before they develop AIDS)
- Are pregnant (because of the theoretical risk that the vaccine virus can infect the foetus)
- Suffer from a very severe egg allergy (as the vaccine virus is cultured in hen’s eggs)
- Are allergic to the antibiotic neomycin (neomycin is used as a preservative in the vaccine)
A rare risk of using the mumps vaccine is meningitis (approximately one person in 100 000 receiving the vaccine). This risk is much lower than in the case of natural mumps infection, where the figure for meningitis is one in 10 people.
The meningitis caused by the vaccine is also mild, without long-term consequences.
When to see a doctor
Although mumps is a fairly easily recognisable illness, especially when there are several children involved, you may want confirmation from your health professional. Any of the other complications of mumps will probably require a visit to a health professional for advice or treatment
A person who has symptoms of neck stiffness, sensitivity to light (photophobia) and severe headache should always be seen by a doctor. Signs of drowsiness or confusion are a medical emergency.
Reviewed by Dr Rowan Dunkley,Paediatrician, Red Cross Children’s Hospital, Cape Town. February 2015
Previously reviewed by Dr Eftyhia Vardas BSc(Hons), MBBCh, DTM&H, DPH, FC Path (Virol), MMed (Virol), Clinical Virologist, Director HIV AIDS Vaccine Division, Perinatal HIV Research Unit, Chris Hani Baragwanath Hospital, University of the Witwatersrand and senior lecturer, Department of Infectious Diseases, Faculty of Health Sciences, University of the Witwatersrand.