Mumps, commonly referred to as mumps, is the inflammation of salivary glands called parotids located behind the ascending branches on both sides of the jaw and is produced by an RNA virus belonging to the paramyxovirus family. It is one of the most common notifiable viral infections.
The only reservoir is the human being and the transmission is aerial so the outbreaks occur mainly in closed places. Although the infection is asymptomatic in a third of cases, the most frequent clinical manifestation is inflammation of the parotid or other salivary glands. Other manifestations are orchitis, encephalitis and pancreatitis.
Since the introduction of universal vaccination in Spain between 1982 and 1985, the incidence of mumps has progressively decreased: in 1983 more than 200,000 cases were reported and in 1993 only slightly more than 6,000.
However, there have been several outbreaks both in Europe and in Spain that have been attributed to a low effectiveness of the vaccine or to the accumulation of susceptible people, since in some countries such as France, there is a significant sector of the population reluctant to vaccinations due to improbable side effects.
The paramyxovirus has a non-segmented negative chain RNA genome with 15,384 bases encoding 8 proteins. N, P and L proteins together exert the polymerase activity that allows transcription and replication of the genome.
Nucleotide sequencing of clinical isolates shows that virus genotypes D and G circulate mainly in the western hemisphere; genotypes F, C and I in the Asia-Pacific region; and genotypes B, H, J and K in the southern hemisphere.
It should be noted that mumps can also affect other organs, such as the male testicles. With an inflammation called orchitis, which if it affects a young adult is very likely to leave as a sequel to hypogonadism and consequently sterility.
The mumps virus is responsible for sterility since the mumps virus infects the Leydig cells in vitro and totally inhibits the secretion of testosterone and protein 10 induced by interferon gamma protein inducer (IP-10).
Interferons that are glycoprotines belonging to the large class of proteins known as cytokines molecules used for communication between cells to trigger the protective defenses of the immune system are highly expressed by Leydig cells infected by the mumps virus.
Ribavirin (ribavirin belongs to a class of antiviral drugs called nucleoside analogues) does not block the production of IP-10, although it restores testosterone production.
In addition to Leydig cells, the mumps virus also infects other cells of the testicle, such as Sertoli cells. These cells may ultimately survive orchitis, but there is a significant loss of spermatogonias, resulting in sesionally acquired Sertoli Single Cell Syndrome in some cases.
In addition to nourishing developing spermatogonia, Sertoli cells are also at the center of immune regulation during adulthood. A physical barrier forms between Sertoli cells and allows these cells to control and regulate the environment of developing germ cells. More importantly, Sertoli cells can secrete immunomodulatory factors that create a privileged immune environment.
Therefore, in men, this myxovirus infects Leydig cells and has harmful effects on the production of testosterone and spermatogenesis, damaging the fertility and sexual life of those who have suffered this trance in post puberty.
This affects between 20 and 30% of those who suffer from mumps and its symptoms are testicular pain, increased volume and occasionally, redness of the scrotal area of the affected testicle, may be unilateral or both, may occur during or after the manifestation of parotid involvement.
In some cases there may be pancreatitis, which is accompanied by other symptoms such as pain in the belly and explosive vomiting to repeat, its diagnosis is made with a blood test that shows the increase of enzymes in the pancreatic gland.
It can also cause meningitis known as urlian encephalitis, which can occur during or after mumps and occurs in less than 10% of cases, with symptoms such as severe headache, explosive vomiting, and physical signs that show neurological involvement (for example, tremor or stiffness in the back of the neck). It is confirmed with an analysis of the cerebrospinal fluid, its prognosis being excellent and in the vast majority, it cures without leaving sequels.
Whenever possible the case will be confirmed by laboratory. If it is not possible to confirm the index case by laboratory or serological study (significant increase in IgG antibodies or presence of IgM antibodies).