What is it?
Mumps is a viral infection. It first causes more general symptoms like fever, muscle pain, headache, and fatigue, but later it can lead to a painful and visible swelling of one or both parotid glands. The symptoms usually resolve within 7-10 days. About 20-40% of those infected don’t show any symptoms.
Without proper immunization, about 0.1% of the population is affected each year. Vaccination has, however, resulted in a decline of more than 90% of the disease.
What causes it?
Mumps is caused by being infected by the mumps virus. It is spread between people through respiratory secretions, such as saliva. This can happen when someone infected for example sneezes or coughs.
What happens during it?
Viruses are not living things: they are DNA-containing protein shells, that invade a cell and turn it into a virus factory. The host cell doesn’t survive this attack, and this damage to the body’s cells together with the immune reaction caused when the body detects the virus, is what causes the majority of symptoms in viral diseases.
It is thought that the mumps virus first invades the respiratory tracts, and moves from there to lymph nodes to replicate. There has initially been only a small amount of viruses in the body, but when they after some days break free from the lymph node cells and start causing havoc in the body, the general flu-like symptoms appear.
The parotid gland is our biggest salivary gland. It secretes saliva into the mouth, and we have one on each side of our head. The most important sign of mumps is the inflammation and swelling of this gland, which happens, when the viruses start replicating in the gland cells and also provoking inflammation from the immune system while doing so. The parotid gland is surrounded by a fibrous envelope, and the swelling of the gland inside this envelope is what causes the pain in mumps. From the parotid gland the viruses are excreted to the saliva. This helps the virus infect others, and an infected person might me able to transmit the virus through this pathway for a time period of over 2 weeks – before and after the onset of symptoms.
How can it be treated?
Mumps is very rarely dangerous, so treatment focuses on relieving symptoms until the immune system has fought off the infection. Getting plenty of rest, drinking water, eating painkillers and applying a warm or cool compress over the swollen glands might help.
Mumps has been effectively prevented with the help of the MMR vaccine. A few years ago, the vaccine was (undeservedly) accused of causing autism, which resulted in many parents deciding to not give their kids the MMR vaccine, and as a result some further mumps outbreaks.
Sources: https://www.researchgate.net/publication/265732096_Molecular_Biology_Pathogenesis_and_Pathology_of_Mumps_Virus, https://en.wikipedia.org/wiki/Mumps, https://en.wikipedia.org/wiki/Parotid_gland, http://www.nhs.uk/Conditions/Mumps/Pages/Treatment.aspx