Clinical significance
The mumps virus belongs to the Paramyxoviridae family and causes acute infections in children aged 5 to 9 and in young adults. The virion is spherical (150-200 nm in diameter), with an outer membrane and a tightly coiled inner nucleocapsid.
The genome consists of RNA and proteins of different molecular weights, classified as S and V antigens.
Only one mumps virus serotype is known. The infection is transmitted through the air or by direct contact.
The infection has two phases: a primary viraemia, in which the virus first replicates in the respiratory or gastrointestinal tract or in the mucous membrane of the eye, then spreads to the lymphatic system and finally to the bloodstream; and a secondary viraemia, in which the virus spreads and replicates further in the parotid gland, but also in the testicles, epididymis, pancreas and ovary.
This second phase is accompanied by clinical symptoms, including muscle aches, headache, moderate fever and general malaise.
Convalescence begins 4-7 days after the parotid gland swells. The virion is excreted in the urine or in breast milk.
During acute infection, specific IgM antibodies appear, followed by a rise in IgG, which then remain for life.
Clinical indications
Determining immune status; essential in cases of orchitis and meningoencephalitis without involvement of the parotid gland.
Sample type
The patient must have a blood sample taken.
Preparation
You must fast for at least 8 hours; a small amount of water is allowed.
Notes
IgG absent, IgM absent: no exposure. If the clinical picture is uncertain, patients should be monitored over time.
IgG present, IgM absent: past infection.
IgG absent, IgM present: very early stage of infection.
IgG present, IgM present: acute or at least recent infection
The mumps virus may cross-react with other paramyxoviruses.