Mumps virus (paramyxovirus parotitis) is distributed worldwide in only one basic form (serotype) and is found exclusively in humans. It is the causative agent of mumps (also called goat mumps, farmer’s wetzel, or booby).
What is the mumps virus?
The mumps virus was first propagated and structured in incubated chicken eggs in 1945. The mumps virus is surrounded by a lipid-containing envelope. It is a single-stranded RNA virus with a spiral capsule. This unusual structure results in a particular sensitivity of the virus to mild soaps as well as desiccation. To date, some genetically slightly divergent subtypes of mumps virus have been found, but this has no relevance to disease or serologic response. Several natural and cultured strains of mumps virus are used in attenuated form as live vaccines. Mumps infection breaks out almost exclusively in childhood and generally results in lifelong immunity to the disease. However, a single vaccination may not protect against mumps for all time.
Occurrence, distribution, and characteristics
According to a current nomenclature, mumps viruses are distinguished by genotypes A through N. The main distribution area of types A, C, D, G, and H is the Western Hemisphere; that of the remaining types is the Asian and Pacific regions. In Germany, mumps has recently been caused mainly by genotype G, which is becoming more common worldwide. However, the disease only extremely rarely has a fatal course, since the virus has adapted very firmly to humans as its so-called reservoir host. The viral infection mumps is characterized by a painful swelling of the salivary glands on the ear. Due to an accumulation of fluid at the sides of the earlobes, the ears appear to stick out and the cheeks on the face look puffy. Children between the ages of two and 15 are most commonly affected by the disease. However, since mumps vaccination has been introduced nationwide, the number of cases in Germany has declined sharply. Infections can occur throughout the year, but are usually concentrated in winter and spring. One disease per 125,000 inhabitants was determined. Mumps is transmitted by droplet infection, direct mucosal contact or occasionally saliva on children’s toys. The virus may also be present in urine and breast milk.
Diseases and symptoms
Mumps virus usually has an incubation period of 16 to 18 days. In some cases, it can extend to 25 days. There is a risk of infection about seven days before and nine days after the typical salivary gland swelling becomes visible. About one-third of all infections with mumps show few or no symptoms. In children under five years of age, mumps is often mistaken for a common cold in mild cases. The disease is usually, but not always, associated with fever. Inflammation of the parotid gland in mumps often begins on one side and then may spread to both sides. Children report the characteristic pain when chewing, in the ears, and when turning the head. Inflammation of the parotid gland may spread to other salivary glands. In rare cases, it may also affect the pancreas. The consequences of this are vomiting and very fatty diarrhea. By itself, however, mumps is rarely associated with major complications, especially in childhood. At an older age, the symptoms can be more severe. After seven to ten days, the disease usually weakens on its own and then soon disappears. Far-reaching consequences can occur when mumps viruses migrate and sometimes affect distant organs and organ systems. In quite a few cases, mumps also worsens into meningitis. This is almost always seen in adulthood. The infection may extend even further to the vestibular nerve. With this progression, there is a risk of inner ear hearing loss or even deafness. Furthermore, inflammation of the testis may occur, again usually in adulthood. This very painful condition can last three to four days and lead to noticeable swelling of the testicle. Bilateral occurrence leads to infertility in serious cases. In many cases, girls and women suffer from ovarian inflammation when the mumps viruses spread, but this is often no longer noticeable after a week.Very rarely, the mumps virus leads to secondary diseases such as encephalitis, inflammation of the thyroid gland, iris, heart muscle and kidneys. The mumps virus cannot be treated with a specific antiviral treatment. The focus of therapy is on pain-relieving and fever-reducing measures. Depending on the patient’s condition, the application of hot or cold compresses may do him good. Light painkillers are also helpful against the swollen parts of the throat. Because of the difficulty in chewing, only porridge-like meals should be taken for a few days. Acidic foods and drinks (such as fruit juices) may increase the pain and are therefore better avoided temporarily. The largely very effective vaccination against the mumps virus, because it is a specific live vaccine, sometimes leads to symptoms of illness (after all, the body is specifically infected with the virus), but in a mild and quickly temporary form. The area around the injection site may become slightly red, swollen and somewhat sore.
