Parotitis

The infectious agent involved in the infection of the disease is the parotytic virus. It belongs to the family Paramyxoviridae, subfamily Paramyxovirinae, of the genus Rubulavirus. It was first isolated in 1934 by Goodpasture and Johnson.
It is a monocatenary RNA virus with negative polarity and an envelope, with a diameter of 100 to 300 nm. Its surface is composed of the hemagglutinin-neurominidase (HN) protein, a cell fusion protein (F) and a matrix protein (M).

Mumps is transmitted primarily by air, particularly by droplets (small particles emitted from the respiratory system during coughing, sneezing or even just talking). The virus is also eliminated with urine and is transmitted transplacentally during gestation, without causing malformations in the fetus.
Usually, the person with mumps is contagious 6-7 days before the appearance of salivary gland swelling and up to 9 days afterwards. Maximum contagiousness occurs in the 48 hours before the onset of these symptoms.

Mumps, as well as measles and rubella, are diseases defined as endemic-epidemic, that is, they have a periodic and continuously present population pattern. Prior to the discovery of vaccination, mumps pandemics occurred every 2 to 5 years, predominantly affecting children under the age of 9. People who met to the disease develop lasting immunity. Mumps epidemics are generally observed during the winter and spring period, especially in closed environments or communities. Since the introduction of the trivalent vaccine (against measles, mumps, and rubella), reported cases have declined sharply. However, low vaccination coverage in different parts of the world still leads to frequent outbreaks. In the United States, several mumps cases that occurred within families, schools, universities, and other places of congregation were reported between 2015 and 2017. From January 2016 to June 2017, 150 outbreaks were recorded with 9200 total cases. From the latest data published on the ECDC website, there were 13,693 cases reported from different states of Europe in the year 2017. Complications due to mumps were rare, affecting 5-7% of cases. Eighty percent of cases were reported from the Czech Republic, Poland, Spain, and the United Kingdom. With a higher prevalence in the male sex, affecting the youngest age group with an age range of 10-19 years even in individuals previously vaccinated with at least one dose. These data bring to light the fundamental importance of active immunization in preventing mumps outbreaks.

Mumps infection generally has an asymptomatic course or with mild respiratory-type symptoms in 50% of cases. In the rest of the cases, the first symptoms begin to appear after an incubation period of about 2 to 3 weeks after the last contact with the infected person. The onset of the disease is characterized by the appearance of fever, headache (headache), myalgias (muscle aches), chills, otalgia (ear pain), anorexia (loss of appetite), and generalized malaise. After about 24 hours, there is enlargement of the parotids, glands located in the retromandibular region (on either side of the ears), but the submandibular and sublingual glands may also be affected. The swelling of these areas is the origin of the disease's popular name "mumps." Mumps tumefaction results in pain on palpation, during chewing and swallowing. In children, generally, the disease has a benign course, without causing any particular damage. Among the complications that can occur, especially after puberty are: orchitis, oophoritis, meningitis or encephalitis, and pancreatitis.

• Orchitis is an infection of the testicles, presenting with pain, edema, erythema and heat in the scrotum. This condition occurs in 30 to 40% of mumps cases in males. Rarely it can lead to infertility.
• Oophoritis is a less frequent condition than orchitis and affects the female gonads, with no correlation with female fertility.
• Meningitis, on the other hand, occurs in 4% to 6% of cases, with an onset of headache, vomiting, nuchal rigidity, and general malaise. Encephalitis even less frequent and is associated with drowsiness, convulsions, and coma.
• Pancreatitis is manifested by severe and sudden nausea, vomiting, and epigastric pain. Generally, these symptoms recede within a week.

Other complications that may be related to mumps are prostatitis, nephritis, myocarditis, hepatitis, mastitis, polyarthritis, and sensorineural deafness due to the direct action of the virus on inner ear cells, but these are very rare. During the gestational period, mumps infection contracted during the first trimester of pregnancy is associated with increased miscarriage. The virus can pass through the placental membrane infecting the product of conception but without causing congenital malformations.

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Diagnosis is made on the basis of history and clinical examination, which is relatively easy to complete because of the characteristic symptoms of the disease. In the absence of complications, laboratory tests reveal no specific data, other than an increase in white blood cell count due to infection.

There is no specific treatment for mumps. In mild forms, rest is sufficient, avoiding solid or sour foods in the acute phase, which can cause pain due to inflamed parotids. Otherwise, medications aimed at symptom control may be prescribed, such as antipyretics for fever (in children under 12 years of age, acetylsalicylic acid is not recommended in favor of acetaminophen) and analgesics for pain.

The only effective tool for preventing the disease is vaccination. This is a mandatory vaccine that is administered in the form of a trivalent or tetravalent vaccine. The trivalent prevents measles, mumps and rubella infections called MPR, while, the quadrivalent prevents infections against measles, mumps, rubella and varicella also called MPRV.