Mumps
Mumps parotitis or mumps virus or mumps is a viral disease primarily reaching infant human salivary glands located in front of the ears and nervous tissue. Now largely controlled by vaccination, it remains widespread in countries undergoing development. Usually without consequences in young children, it can cause serious complications when contracted in adulthood, including male infertility due to impairment of the testes (orchitis).
The name is only used in plural (mumps) and from the fact that one of the clinical signs of the disease is pain in the ears associated with inflammation of parotid glands. The adjective is associated with mumps, the vector of the disease is so named mumps virus.
His code is B26 according to the list of ICD-10 disease.
Epidemiology
Before widespread vaccination, mumps outbreak occurred in a seasonal pattern, usually in late winter and spring in temperate climates, with a period of 4 to 5 years, especially in institutions Home group of young children (nursery school). The disease was very common since almost 90% of teens have a positive mumps serology.
The vaccine has almost completely eliminated forms of childhood and has paradoxically increased the number of cases among young adults, who often received incomplete vaccination, but sometimes correctly vaccinated.
Monitoring trends in incidence in France is conducted by the sentinel network of Inserm.
Cause and mechanism
The mumps virus is a paramyxovirus, myxovirus parotid RNA virus and is transmitted from person to person through air by droplets of saliva or direct contact with infected saliva, for example.
The virus replicates in the oro-pharyngeal apparatus where it can spread to the whole body through the bloodstream.
The parotid glands (salivary glands located between the ear and jaw) are usually affected. The virus develops there producing local edema with infiltration of lymphocytes and macrophages. Unvaccinated children between 2 and 12 years are most commonly affected, but infection occurs in other age groups.
The child is contagious for about two weeks, a few days before signs appear until several days after recovery.
The edema may cause some tissue necrosis and lead on the testes, atrophy (becoming smaller) of the latter. The virus can also pass into the central nervous system through the blood-brain barrier and the fetus through the blood-placental barrier.
Signs
Incubation lasts about three weeks (15 to 24 days).
The invasion phase of short duration, manifested by fever, malaise, otalgia (earache). The review can be found then a pain in the parotid glands pressure
In the critical stage, which lasts about a week, is marked by fever and headache. There is a unilateral or bilateral swelling of parotid glands with a pain that radiates to the ears of discomfort or pain when chewing. The achievement of both parotid glands may be simultaneous but often lagged several days. Clinical examination found lymphadenopathy (lymph nodes increased in size). Involvement of other salivary glands is rare.
Biology
The diagnosis is mainly based on symptoms and clinical examination and it is usually unnecessary to require further examinations.
The blood count is normal. The rate of blood amylase is increased, the damage is parotid or pancreas.
In cases of meningitis, lumbar puncture brings a clear liquid ( "crystal") and his analysis shows an increased number of lymphocytes as in viral meningitis.
The virus can be isolated in the saliva, cerebrospinal fluid or urine. It is rarely found in the blood. It can also be cultured. Historically, it was characterized in this way by observing its effect on cells. Currently, he is identified using the PCR techniques on tissue infected with a performance far superior to simple planting, particularly in the cerebrospinal fluid.
Serology (determination of antibodies against mumps virus) also confirms the diagnosis of disease in cases of doubt. IgM is detectable a few days after the first signs. They may however be normal if a new infection with mumps virus from a different serotype (or after vaccination). The increase of IgG in two separate samples of fifteen days may then be an indication of impairment by illness.
Evolution
Its evolution is usually benign or asymptomatic in approximately one third of cases. Another third of cases manifest with signs of influenza disease nonspecific and only in the last third is a painful swelling of parotid glands, typical sign of the disease.
The disease confers lifelong immunity, even when asymptomatic, but concerns only the serotype of mumps virus in question, making it theoretically possible new disease. The geographical distribution of different serotypes are a new infection is in practice uncommon.
Complications
A orchidomegalie (swollen testes) will appear in 15 to 30% of adults infected men. It is bilateral in approximately one quarter of cases. It progresses to a decrease in testicular size achieved in just under 50% of cases, more rarely, decreased sperm count, leading rarely to infertility. Hormone production by the affected testicle seems unaffected. Similarly, orchitis appears to be a risk factor for testicular cancer.
Viral meningitis is seen in about 5% of infections and occurs most often after reaching parotid but may appear so completely isolated. Like any meningitis, it is manifested by fever, headache, stiff neck. Its evolution is typically benign. In rare cases, a lethargy with convulsions may occur, signing encephalitis. The evolution is favorable in almost all cases.
A unilateral hearing loss and transient, especially for high frequencies, may complicate the disease.
In the elderly, other organs may be affected, as the central nervous system, pancreas, prostate, breast and other organs.
During pregnancy, mumps can cause miscarriage relatively early, but it does not seem to increase risk of birth defects.
Treatment
There is no specific treatment for mumps. Symptoms can be relieved by bed rest, application of intermittent ice or heat on the neck area affected, antipyretics and analgesics such as paracetamol orally to relieve pain. Do not give aspirin to children with viral disease given the risk of Reye syndrome. Gargle with warm salt water, sweet foods and fluid intake can also help relieve symptoms.
Fruit juices should be avoided because they stimulate the salivary glands, with pain that follows.
Vaccination
The mumps vaccine has existed since 1968.
Prevention is based on the vaccination is done in isolation or associated with measles and rubella. This vaccination is recommended during childhood. It recommends 2 doses of vaccine. The first 12 months and the second during the second year, that is to say between the 13th and 24th months, and not between 3 and 6 years! The immunization coverage rate exceeds 95% in industrialized countries resulting in a similar reduction in the incidence of the disease.
The vaccine is a live attenuated virus and is currently directed against several viral serotypes. It is valid, effective, but some strains are more resistant.
The vaccine was well tolerated. Rarely, it can cause aseptic meningitis benign.
Read also Vaccination
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