• Source: Mumps

Mumps is a highly contagious viral disease caused by the mumps virus. Initial symptoms of mumps are non-specific and include fever, headache, malaise, muscle pain, and loss of appetite. These symptoms are usually followed by painful swelling around the side of the face (the parotid glands, called parotitis), which is the most common symptom of a mumps infection. Symptoms typically occur 16 to 18 days after exposure to the virus. About one third of people with a mumps infection do not have any symptoms (asymptomatic).
Complications are rare but include deafness and a wide range of inflammatory conditions, of which inflammation of the testes, breasts, ovaries, pancreas, meninges, and brain are the most common. Viral meningitis can occur in 1/4 of people with mumps. Testicular inflammation may result in reduced fertility and, rarely, sterility.
Humans are the only natural host of the mumps virus. The mumps virus is an RNA virus in the family Paramyxoviridae. The virus is primarily transmitted by respiratory secretions such as droplets and saliva, as well as via direct contact with an infected person. Mumps is highly contagious and spreads easily in densely populated settings. Transmission can occur from one week before the onset of symptoms to eight days after. During infection, the virus first infects the upper respiratory tract. From there, it spreads to the salivary glands and lymph nodes. Infection of the lymph nodes leads to presence of the virus in blood, which spreads the virus throughout the body. In places where mumps is common, it can be diagnosed based on clinical presentation. In places where mumps is less common, however, laboratory diagnosis using antibody testing, viral cultures, or real-time reverse transcription polymerase chain reaction may be needed.
There is no specific treatment for mumps, so treatment is supportive in nature and includes rest and pain relief. Mumps infection is usually self-limiting, coming to an end as the immune system clears the infection. Infection can be prevented with vaccination. The MMR vaccine is a safe and effective vaccine to prevent mumps infections and is used widely around the world. The MMR vaccine also protects against measles and rubella. The spread of the disease can also be prevented by isolating infected individuals.
Mumps historically has been a highly prevalent disease, commonly occurring in outbreaks in densely crowded spaces. In the absence of vaccination, infection normally occurs in childhood, most frequently at the ages of 5–9. Symptoms and complications are more common in males and more severe in adolescents and adults. Infection is most common in winter and spring in temperate climates, whereas no seasonality is observed in tropical regions. Written accounts of mumps have existed since ancient times, and the cause of mumps, the mumps virus, was discovered in 1934. By the 1970s, vaccines had been created to protect against infection, and countries that have adopted mumps vaccination have seen a near-elimination of the disease. In the 21st century, however, there has been a resurgence in the number of cases in many countries that vaccinate, primarily among adolescents and young adults, due to multiple factors such as waning vaccine immunity and opposition to vaccination.




Etymology


The word "mumps" is first attested circa 1600 and is the plural form of "mump", meaning "grimace", originally a verb meaning "to whine or mutter like a beggar". The disease was likely called mumps in reference to the swelling caused by mumps parotitis, reflecting its impact on facial expressions and the painful, difficult swallowing that it causes. "Mumps" was also used starting from the 17th century to mean "a fit of melancholy, sullenness, silent displeasure". Mumps is sometimes called "epidemic parotitis".




History


According to Chinese medical literature, mumps was recorded as far back as 640 B.C. The Greek physician Hippocrates documented an outbreak on the island of Thasos in approximately 410 B.C. and provided a fuller description of the disease in the first book of Epidemics in the Corpus Hippocraticum. In modern times, the disease was first described scientifically in 1790 by British physician Robert Hamilton in Transactions of the Royal Society of Edinburgh. During the First World War, mumps was one of the most debilitating diseases among soldiers. In 1934, the etiology of the disease, the mumps virus, was discovered by Claude D. Johnson and Ernest William Goodpasture. They found that rhesus macaques exposed to saliva taken from humans in the early stages of the disease developed mumps. Furthermore, they showed that mumps could then be transferred to children via filtered and sterilized, bacteria-less preparations of macerated monkey parotid tissue, showing that it was a viral disease.
In 1945, the mumps virus was isolated for the first time. Just a few years later, in 1948, an inactivated vaccine using killed viruses was invented. This vaccine provided only short-term immunity and was later discontinued. It was replaced in the 1970s with vaccines that have live but weakened viruses, which are more effective at providing long-term immunity than the inactivated vaccine. The first of these vaccines was Mumpsvax, licensed on 30 March 1967, which used the Jeryl Lynn strain. Maurice Hilleman created this vaccine using the strain taken from his five-year-old daughter, Jeryl Lynn. Mumpsvax was recommended for use in 1977, and the Jeryl Lynn strain continues to be used.
Hilleman worked to combine the attenuated mumps vaccines with measles and rubella vaccines, creating the MMR-1 vaccine. In 1971, a newer version, MMR-2, was approved for use by the US Food and Drug Administration. In the 1980s, the benefit of multiple doses was recognized, so a two-dose immunization schedule was widely adopted. With MMR-2, four other MMR vaccines have been created since the 1960s: Triviraten, Morupar, Priorix, and Trimovax. Since the mid-2000s, two MMRV vaccines have been in use: Priorix-Tetra and ProQuad.
The United States began to vaccinate against mumps in the 1960s, with other countries following suit. From 1977 to 1985, 290 cases per 100,000 people were diagnosed each year worldwide. Although few countries recorded mumps cases after they began vaccination, those that did reported dramatic declines. From 1968 to 1982, cases declined by 97% in the U.S., in Finland cases were reduced to less than one per 100,000 people per year, and a decline from 160 cases per 100,000 to 17 per 100,000 per year in England was observed from 1989 to 1995. By 2001, there had been a 99.9% reduction in the number of cases in the U.S. and similar near-elimination in other vaccinating countries.
In Japan in 1993, concerns over the rates of aseptic meningitis following MMR vaccination with the Urabe strain prompted the removal of MMR vaccines from the national immunization program, resulting in a dramatic increase in the number of cases. Japan provides voluntary mumps vaccination separately from measles and rubella. Starting in the mid-1990s, controversies surrounding the MMR vaccine emerged. One paper connected the MMR vaccine to Crohn's disease in 1995, and another in 1998 connected it to autism spectrum disorders and inflammatory bowel disease. These papers are now considered to be fraudulent and incorrect, and no association between the MMR vaccine and the aforementioned conditions has been identified. Despite this, their publication led to a significant decline in vaccination rates, ultimately causing measles, mumps, and rubella to reemerge in places with lowered vaccination rates.
Outbreaks in the 21st century include more than 300,000 cases in China in 2013 and more than 56,000 cases in England and Wales in 2004–2005. In the latter outbreak, most cases were reported in 15–24 year olds who were attending colleges and universities. This age group was thought to be vulnerable to infection because of the MMR vaccine controversies when they should have been vaccinated or MMR vaccine shortages that had also occurred at that time. Similar outbreaks in densely crowded environments have frequently occurred in many other countries, including the U.S., the Netherlands, Sweden, and Belgium.




= Resurgence

=

In the 21st century, mumps has reemerged in many places that vaccinate against it, causing recurrent outbreaks. These outbreaks have largely affected adolescents and young adults in densely crowded spaces, such as schools, sports teams, religious gatherings, and the military, and it is expected that outbreaks will continue to occur. The cause of this reemergence is subject to debate, and various factors have been proposed, including waning immunity from vaccination, low vaccination rates, vaccine failure, and potential antigenic variation of the mumps virus.
Waning immunity from vaccines is likely the primary cause of the mumps resurgence. In the past, subclinical natural infections provided boosts to immunity similar to vaccines. As time went on with vaccine use, these asymptomatic infections declined in frequency, likely leading to a reduction in long-term immunity against mumps. With less long-term immunity, the effects of waning vaccine immunity became more prominent, and vaccinated individuals have frequently fallen ill from mumps. A third dose of the vaccine provided in adolescence has been considered to address this as some studies support this. Other research indicates that a third dose may be useful only for short-term immunity in responding to outbreaks, which is recommended for at-risk persons by the Advisory Committee on Immunization Practices of the Centers for Disease Control and Prevention.
Low vaccination rates have been implicated as the cause of some outbreaks in the UK, Canada, Sweden, and Japan, whereas outbreaks in other places, such as the U.S., the Czech Republic, and the Netherlands, have occurred mainly among the vaccinated. Compared to the measles and rubella vaccines, mumps vaccines appear to have a relatively high failure rate, varying depending on the vaccine strain. This has been addressed by providing two vaccine doses, supported by recent outbreaks among the vaccinated having primarily occurred among those who received only one dose. Lastly, certain mumps virus lineages are highly divergent genetically from vaccine strains, which may cause a mismatch between protection against vaccine strains and non-vaccine strains, though research is inconclusive on this matter.




Signs and symptoms






= Common symptoms

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The incubation period, the time between the start of infection and when symptoms begin to show, is about 7–25 days, averaging 16–18 days. 20–40% of infections are asymptomatic or are restricted to mild respiratory symptoms, sometimes with a fever. Over the course of the disease, three distinct phases are recognized: prodromal, early acute, and established acute. The prodromal phase typically has non-specific, mild symptoms such as a low-grade fever, headache, malaise, muscle pain, loss of appetite, and sore throat. In the early acute phase, as the mumps virus spreads throughout the body, systemic symptoms emerge. Most commonly, parotitis occurs during this time period. During the established acute phase, orchitis, meningitis, and encephalitis may occur, and these conditions are responsible for the bulk of mumps morbidity.
The parotid glands are salivary glands situated on the sides of the mouth in front of the ears. Inflammation of them, called parotitis, is the most common mumps symptom and occurs in about 90% of symptomatic cases and 60–70% of total infections. During mumps parotitis, usually both the left and right parotid glands experience painful swelling, with unilateral swelling in a small percentage of cases. Parotitis occurs 2–3 weeks after exposure to the virus, within two days of developing symptoms, and usually lasts 2–3 days, but it may last as long as a week or longer.
In 90% of parotitis cases, swelling on one side is delayed rather than both sides swelling in unison. The parotid duct, which is the opening that provides saliva from the parotid glands to the mouth, may become red, swollen, and filled with fluid. Parotitis is usually preceded by local tenderness and occasionally earache. Other salivary glands, namely the submandibular, and sublingual glands, may also swell. Inflammation of these glands is rarely the only symptom.




= Complications

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Outside of the salivary glands, inflammation of the testes, called orchitis, is the most common symptom infection. Pain, swelling, and warmness of a testis appear usually 1–2 weeks after the onset of parotitis but can occur up to six weeks later. During mumps orchitis, the scrotum is tender and inflamed. It occurs in 10–40% of pubertal and post-pubertal males who contract mumps. Usually, mumps orchitis affects only one testis but in 10–30% of cases both are affected. Mumps orchitis is accompanied by inflammation of the epididymis, called epididymitis, about 85% of the time, typically occurring before orchitis. The onset of mumps orchitis is associated with a high-grade fever, vomiting, headache, and malaise. In prepubertal males, orchitis is rare as symptoms are usually restricted to parotitis.
A variety of other inflammatory conditions may also occur as a result of mumps virus infection, including:

Mastitis, inflammation of the breasts, in up to about 30% of post-pubertal women
Oophoritis, inflammation of an ovary, in 5–10% of post-pubertal women, which usually presents as pelvic pain
Aseptic meningitis, inflammation of the meninges, in 5–10% of cases and 4–6% of those with parotitis, typically occurring 4–10 days after the onset of symptoms. Mumps meningitis can also occur up to one week before parotitis as well as in the absence of parotitis. It is commonly accompanied by fever, headache, vomiting, and neck stiffness.
Pancreatitis, inflammation of the pancreas, in about 4% of cases, which causes severe pain and tenderness in the upper abdomen below the ribs
Encephalitis, inflammation of the brain, in less than 0.5% of cases. People who experience mumps encephalitis typically experience a fever, altered consciousness, seizures, and weakness. Like meningitis, mumps encephalitis can occur in the absence of parotitis.
Meningoencephalitis, inflammation of the brain and its surrounding membranes. Mumps meningoencephalitis is commonly accompanied by fever 97% of the time, vomiting 94% of the time, and headache 88.8% of the time.
Nephritis, inflammation of the kidneys, which is rare because kidney involvement in mumps is usually benign but leads to presence of the virus in urine
Inflammation of the joints (arthritis), which may affect at least five joints (polyarthritis), multiple nerves in the peripheral nervous system (polyneuritis), pneumonia, gallbladder without gallstones (acalculous cholecystitis), cornea and uveal tract (keratouveitis), thyroids (thyroiditis), liver (hepatitis), retina (retinitis), and corneal endothelium (corneal endothelitis), all of which are rare
Recurrent sialadenitis, inflammation of the salivary glands, which is frequent
A relatively common complication is deafness, which occurs in about 4% of cases. Mumps deafness is often accompanied by vestibular symptoms such as vertigo and repetitive, uncontrolled eye movements. Based on electrocardiographic abnormalities in the infected, MuV also likely infects cardiac tissue, but this is usually asymptomatic. Rarely, myocarditis and pericarditis can occur. Fluid buildup in the brain, called hydrocephalus, has also been observed. In the first trimester of pregnancy, mumps may increase the risk of miscarriage. Otherwise, mumps is not associated with birth defects.
Other rare complications of infection include: paralysis, seizures, cranial nerve palsies, cerebellar ataxia, transverse myelitis, ascending polyradiculitis, a polio-like disease, arthropathy, autoimmune hemolytic anemia, idiopathic thrombocytopenic purpura, Guillain–Barré syndrome, post-infectious encephalitis encephalomyelitis, and hemophagocytic syndrome. At least one complication occurs in combination with the standard mumps symptoms in up to 42% of cases. Mumps has also been connected to the onset of type 1 diabetes, and, relatedly, the mumps virus is able to infect and replicate in insulin-producing beta cells. Among children, seizures occur in about 20–30% of cases involving the central nervous system.




Cause


Mumps is caused by the mumps virus (MuV), scientific name Mumps orthorubulavirus, which belongs to the Orthorubulavirus genus in the Paramyxoviridae family of viruses. Humans are the only natural host of the mumps virus. MuV's genome is made of RNA and contains seven genes that encode nine proteins. In MuV particles, the genome is encased by a helical capsid. The capsid is surrounded by a viral envelope that has spikes protruding from its surface. MuV particles are pleomorphic in shape and range from 100 to 600 nanometers in diameter.
The replication cycle of MuV begins when the spikes on its surface bond to a cell, which then causes the envelope to fuse with the host cell's cell membrane, releasing the capsid into the host cell's cytoplasm. Upon entry, the viral RNA-dependent RNA polymerase (RdRp) transcribes messenger RNA (mRNA) from the genome, which is then translated by the host cell's ribosomes to synthesize viral proteins. RdRp then begins replicating the viral genome to produce progeny. Viral spike proteins fuse into the host cell's membrane, and new virions are formed at the sites beneath the spikes. MuV then utilizes host cell proteins to leave the host cell by budding from its surface, using the host cell's membrane as the viral envelope.
Twelve genotypes of MuV are recognized, named genotypes A to N, excluding E and M. These genotypes vary in frequency from region to region. For example, genotypes C, D, H, and J are more common in the western hemisphere, whereas genotypes F, G, and I are more common in Asia, although genotype G is considered to be a global genotype. Genotypes A and B have not been observed in the wild since the 1990s. MuV has just one serotype, so antibodies to one genotype are functional against all genotypes. MuV is a relatively stable virus and is unlikely to experience antigenic shifting that may cause new strains to emerge.




Transmission


The mumps virus is mainly transmitted by inhalation or oral contact with respiratory droplets or secretions. In experiments, mumps could develop after inoculation either via the mouth or the nose. Respiratory transmission is also supported by the presence of MuV in cases of respiratory illness without parotitis, detection in nasal samples, and transmission between people in close contact. MuV is excreted in saliva from approximately one week before to eight days after the onset of symptoms, peaking at the onset of parotitis, though it has also been identified in the saliva of asymptomatic individuals.
Mother-to-child transmission has been observed in various forms. In non-human primates, placental transmission has been observed, which is supported by isolation of MuV from spontaneous and planned aborted fetuses during maternal mumps. MuV has also been isolated from newborns whose mother was infected. While MuV has been detected in breast milk, it is unclear if the virus can be transmitted through it. Other manners of transmission include direct contact with infected droplets or saliva, fomites contaminated by saliva, and possibly urine. Most transmissions likely occur before the development of symptoms and up to five days after such time.
In susceptible populations, a single case can cause up to twelve new ones. The time period when a person is contagious lasts from two days before the onset of symptoms to nine days after symptoms have ceased. Asymptomatic carriers of the mump virus can also transmit the virus. These factors are thought to be reasons why controlling the spread of mumps is difficult. Furthermore, reinfection can occur after a natural infection or vaccination, indicating that lifelong immunity is not guaranteed after infection. Vaccinated individuals who are infected appear to be less contagious than the unvaccinated.
The average number of new cases generated from a single case in a susceptible population, called the basic reproduction number, is 4–7. Given this, it is estimated that a vaccination rate between 79 and 100% is needed to achieve herd immunity. Outbreaks continue to occur in places that have vaccination rates exceeding 90%, however, suggesting that other factors may influence disease transmission. Outbreaks that have occurred in these vaccinated communities typically occur in highly crowded areas such as school and military dormitories.




Pathogenesis


Many aspects of the pathogenesis of mumps are poorly understood and are inferred from clinical observations and experimental infections in laboratory animals. These animal studies may be unreliable due to unnatural methods of inoculation. Following exposure, the virus infects epithelial cells in the upper respiratory tract that express sialic acid receptors on their surface. After infection, the virus spreads to the parotid glands, causing the signature parotitis. It is thought that shortly after infection the virus spreads to lymph nodes, in particular T-cells and viruses in the blood, called viremia. Viremia lasts for 7–10 days, during which MuV spreads throughout the body.
In mumps orchitis, infection leads to: parenchymal edema; congestion, or separation, of the seminiferous tubules; and perivascular infiltration by lymphocytes. The tunica albuginea forms a barrier against edema, causing an increase in intratesticular pressure that causes necrosis of the seminiferous tubules. The seminiferous tubules also experience hyalinization, i.e. degeneration into a translucent glass-like substance, which can cause fibrosis and atrophy of the testes.
In up to half of cases, MuV infiltrates the central nervous system (CNS), where it may cause meningitis, encephalitis, or hydrocephalus. Mumps is rarely fatal, so few post-mortem analyses have been done to analyze CNS involvement. Of these, fluid buildup, congestion, and hemorrhaging in the brain, white blood cell infiltration in the perivascular spaces in the brain, reactive changes to glial cells and damage to the myelin sheaths surrounding neurons were observed. Neurons appear to be relatively unaffected.
In laboratory tests on rodents, MuV appears to enter the CNS first through cerebrospinal fluid (CSF), then spreading to the ventricular system. There, MuV replicates in ependymal cells that line the ventricles, which allows the virus to enter the brain parenchyma. This often leads to MuV infecting pyramidal cells in the cerebral cortex and hippocampus. Infected ependymal cells become inflamed, lose their cilia, and collapse into CSF, which may be the cause of the narrowing of the cerebral aqueduct thought to cause mumps hydrocephalus.
In humans, mumps hydrocephalus may be due to obstruction of the cerebral aqueduct with dilatation of the lateral and third ventricles, obstruction of the interventricular foramina, or obstruction of the median and lateral apertures. Ependymal cells have been isolated from CSF of mumps patients, suggesting that animals and humans share hydrocephalus pathogenesis. Hydrocephalus has also been observed in the absence of canal obstruction, however, indicating that obstruction may be a result of external compression by edematous tissue and not related to hydrocephalus.
Deafness from mumps may be caused by MuV infection in CSF, which has contact with the perilymph of the inner ear, possibly leading to infection of the cochlea, or it may occur as a result of inner ear infection via viremia that leads to inflammation in the endolymph. Hearing loss may also be caused indirectly by the immune response. In animal studies, MuV has been isolated from the vestibular ganglion, which may explain vestibular symptoms such as vertigo that often co-occur with deafness.




Immune response


Even though MuV has just one serotype, significant variation in the quantity of genotype-specific sera needed to neutralize different genotypes in vitro has been observed. Neutralizing antibodies in the salivary glands may be important in restricting MuV replication and transmission via saliva, as the level of viral secretion in saliva inversely correlates to the quantity of MuV-specific IgA produced. The neutralizing ability of salivary IgA appears to be greater than serum IgG and IgM.
It has been proposed that symptomatic infections in the vaccinated may be because memory T lymphocytes generated as a result of vaccination may be necessary but insufficient for protection. The immune system in general appears to have a relatively weak response to the mumps virus, indicated by various measures: antibody production appears to be predominately directed toward non-neutralizing viral proteins, and there may possibly be a low quantity of MuV-specific memory B lymphocytes. The amount of antibodies needed to confer immunity is unknown.




Diagnosis


In places where mumps is widespread, diagnosis can be made based on development of parotitis and history of exposure to someone with mumps. In places where mumps is less common, because parotitis has other causes, laboratory diagnosis may be needed to verify mumps infection. A differential diagnosis may be used to compare symptoms to other diseases, including allergic reaction, mastoiditis, measles, and pediatric HIV infection and rubella. MuV can be isolated from saliva, blood, the nasopharynx, salivary ducts, and seminal fluid within one week of the onset of symptoms, as well as from cell cultures. In meningitis cases, MuV can be isolated from CSF. In CNS cases, a lumbar puncture may be used to rule out other potential causes, which shows normal opening pressure, more than ten leukocytes per cubic millimeter, elevated lymphocyte count in CSF, polymorphonuclear leukocytes up to 25% of the time, often a mildly elevated protein level, and a slightly reduced CSF glucose to blood glucose ratio up to 30% of the time.
Mumps-specific IgM antibodies in serum or oral fluid specimens can be used to identify mumps. IgM quantities peak up to eight days after the onset of symptoms, and IgM can be measured by enzyme-linked immunosorbent assays (ELISA) 7–10 days after the onset of symptoms. Sensitivity to IgM testing is variable, ranging from as low as 24–51% to 75% in the first week and 100% thereafter. Throughout infection, IgM titres increase four-fold between the acute phase and recovery. False negatives can occur in people previously infected or vaccinated, in which case a rise of serum IgG may be more useful for diagnosis. False positives can occur after infection of parainfluenza viruses 1 and 3 and Newcastle disease virus as well as recently after mumps vaccination.
Antibody titers can also be measured with complement fixation tests, hemagglutination assays, and neutralization tests. In vaccinated people, antibody-based diagnosis can be difficult since IgM oftentimes cannot be detected in acute phase serum samples. In these instances, it is easier to identify MuV RNA from oral fluid, a throat swab, or urine. In meningitis cases, MuV-specific IgM can be found in CSF in half of cases, and IgG in a 30–90%, sometimes lasting for more than a year with increased white blood cell count. These findings are not associated with increased risk of long-term complications. Most parotitis cases have elevated white blood cell count in CSF.
Real-time reverse transcription polymerase chain reaction (rRT-PCR) can be used to detect MuV RNA from the first day symptoms appear, declining over the next 8–10 days. rRT-PCR of saliva is typically positive from 2–3 days before parotitis develops to 4–5 days after and has a sensitivity of about 70%. Since MuV replicates in kidneys, viral culture and RNA detection in urine can be used for diagnosis up to two weeks after symptoms begin, though rRT-PCR used to identify the virus in urine has a very low sensitivity compared to virus cultures at below 30%. In meningoencephalitis cases, a nested RT-PCR is able to detect MuV RNA in CSF up to two years after infection.
In sialadenitis cases, imaging shows enlargement of the salivary glands, fat stranding, and thickening of the superficial cervical fascia and platysma muscles, which are situated on the front side of the neck. If parotitis occurs only on one side, then detection of mumps-specific IgM antibodies, IgG titer, or PCR is required for diagnosis. In cases of pancreatitis, there may be elevated levels of lipase or amylase, an enzyme found in saliva and the pancreas.
Mumps orchitis is usually diagnosed by white blood cell count, with normal differential white blood cell counts. A complete blood count can show above or below average white blood cell count and an elevated C-reactive protein level. Urine analysis can exclude bacterial infections. If orchitis is present with normal urine analysis, negative urethral cultures, and negative midstream urine, then that can indicate mumps orchitis. Ultrasounds typically show diffuse hyper-vascularity, increased volume of the testes and epididymis, lower than usual ability to return ultrasound signals, swelling of the epididymis, and formation of hydroceles. Echo color doppler ultrasound is more effective at detecting orchitis than ultrasound alone.




Prevention



Mumps is preventable with vaccination. Mumps vaccines use live attenuated viruses. Most countries include mumps vaccination in their immunization programs, and the MMR vaccine, which also protects against measles and rubella, is the most commonly used mumps vaccine. Mumps vaccination can also be done on its own and as a part of the MMRV vaccine, which also provides protection against measles, rubella, chickenpox, and shingles. More than 120 countries have adopted mumps vaccination, but coverage remains low in most African, South Asian, and Southeast Asian countries. In countries that have implemented mumps vaccination, significant declines in mumps cases and complications caused by infection such as encephalitis have been observed. Mumps vaccines are typically administered in early childhood, but may also be given in adolescence and adulthood if need be. Vaccination is expected to be capable of neutralizing wild-type MuVs, which are not included in the vaccine, since they do not appear to evade vaccine-derived immunity.
A variety of virus strains have been used in mumps vaccines, including the Jeryl Lynn (JL), Leningrad-3, Leningrad-3-Zagreb (L-Zagreb), Rubini, and Urabe AM9 strains. Some other less prominent strains exist that are typically confined to individual countries. These include the Hoshino, Miyahara, Torii, and NK M-46 strains that have been produced in Japan and the S-12 strain, which is used by Iran. Mild adverse reactions are relatively common, including fever and rash, but aseptic meningitis also occurs at varying rates. Other rare adverse reactions include meningoencephalitis, parotitis, deafness from inner ear damage, orchitis, and pancreatitis. Safety and effectiveness vary by vaccine strain:

Rubini is safe but because of its low effectiveness in outbreaks, its use has been abandoned.
JL is relatively safe and has a relatively high effectiveness. However, the effectiveness is significantly lower in outbreaks. A modified version of JL vaccines is RIT 4385, which is also considered safe.
Urabe and Leningrad-3 are both at least as effective as JL, but are less safe.
L-Zagreb, a modified version of Leningrad-3, is considered safe and effective, including in outbreaks.
Mumps protection from the MMR vaccine is higher after two doses than one and is estimated to be between 79% and 95%, lower than the degree of protection against measles and rubella. This, however, has still been sufficient to nearly eliminate mumps in countries that vaccinate against it as well as significantly reduce frequencies of complications among the vaccinated. If at least one dose is received, then hospitalization rates are reduced by an estimated 50% among the infected. Compared to the MMR vaccine, the MMRV vaccine appears to be less effective in terms of providing mumps protection. A difficulty in assessing vaccine effectiveness is that there is no clear correlate of immunity, so it is not possible to predict if a person has acquired immunity from the vaccine.
There is a lack of data on the effectiveness of a third dose of the MMR vaccine. In an outbreak in which a third dose was administered, it was unclear if it had any effect on reducing disease incidence, and it only appeared to boost antibodies in those who previously had little or no antibodies to mumps. Contraindications for mumps vaccines include prior allergic reaction to any ingredients or to neomycin, pregnancy, immunosuppression, a moderate or severe illness, having received a blood product recently, and, for MMRV vaccines specifically, a personal or familial history of seizures. It is also advised that women not become pregnant in the four weeks after MMR vaccination. No effective prophylaxis exists for mumps after one has been exposed to the virus, so vaccination or receiving immunoglobulin after exposure does not prevent progression to illness.
For people who are infected or suspected to be infected, isolation is important in preventing the spread of the disease. This includes abstaining from school, childcare, work, and other settings in which people gather together. In health care settings, it is recommended that health care workers use precautions such as face masks to reduce the likelihood of infection and to abstain from work if they develop mumps. Additional measures taken in health care facilities include reducing wait times for mumps patients, having mumps patients wear masks, and cleaning and disinfecting areas that mumps patients use. The virus can be inactivated by means of formalin, ether, chloroform, heat, or ultraviolet light.




Treatment


Mumps is usually self-limiting, and no specific antiviral treatments exist for it, so treatment is aimed at alleviating symptoms and preventing complications. Non-medicinal ways to manage the disease include bed rest, using ice or heat packs on the neck and scrotum, consuming more fluids, eating soft food, and gargling with warm salt water. Anti-fever medications may be used during the febrile period, excluding aspirin when given to children, which may cause Reye syndrome. Analgesics may also be provided to control pain from mumps inflammatory conditions. For seizures, anticonvulsants may be used. In severe neurological cases, ventilators may be used to support breathing.
Intramuscular mumps immunoglobulin may be of benefit when administered early in some cases, but it has not shown benefit in outbreaks. Although not recommended, intravenous immunoglobulin therapy may reduce the rates of some complications. Antibiotics may be used as a precaution in cases in which bacterial infection cannot be ruled out as well as to prevent secondary bacterial infection. Autoimmune-based disorders connected to mumps are treatable with intravenous immunoglobulin.
Various types of treatment for mumps orchitis have been used, but no specific treatment is recommended due to each method's limitations. These measures are primarily based around relieving testicular pain and reducing intratesticular pressure to reduce the likelihood of testicular atrophy. Interferon-α2α interferes with viral replication, so it has been postulated to be useful in preventing testicular damage and infertility. Interferon alfa-2b may reduce the duration of symptoms and incidence of complications. In cases of hydrocele formation, excess fluid can be removed.
Acupuncture has been used fairly widely in China to treat children who have mumps, however, no high quality trials have been conducted to determine the safety or effectiveness of this treatment approach.




Prognosis


Prognosis for most people who experience mumps is excellent as long-term complications and death are rare. Hospitalization is typically not required. Mumps is usually self-limiting and symptoms resolve spontaneously within two weeks as the immune system clears the virus from the body. In high-risk groups such as immunocompromised persons, prognosis is considered to be the same as for other groups. For most people, infection leads to lifelong immunity against future infection. Reinfections appear to be more mild and atypical than the first infection. The overall case-fatality rate of mumps is 1.6–3.8 people per 10,000, and these deaths typically occur in those who develop encephalitis.
Mumps orchitis typically resolves within two weeks. In 20% of cases, the testicles may be tender for a few more weeks. Atrophy, or reduction of size, of the involved testicle occurs in 30–50% of orchitis cases, which may lead to abnormalities in sperm creation and fertility such as low sperm count, absence of sperm in semen, reduced sperm motility, reduced fertility (hypofertility) in 13% of cases, and rarely sterility. Hypofertility can, however, occur in cases without atrophy. Abnormalities in sperm creation can persist for months to years after recovery from the initial infection, the length of which increases as the severity of orchitis increases. Examination of these cases shows decreased testicular volume, tenderness of the testicles, and a feeling of inconsistency when handling the testicles. Infertility is linked to severe cases of orchitis affecting both testes followed by testicular atrophy, which may develop up to one year after the initial infection. Of bilateral orchitis cases, 30–87% experience infertility. There is a weak association between orchitis and later development of epididymitis and testicular tumors.
Mumps meningitis typically resolves within 3–10 days without long-term complications. In meningoencephalitis cases, higher protein levels in CSF and a lower CSF glucose to blood glucose ratio are associated with longer periods of hospitalization. Approximately 1% of those whose CNS is affected die from mumps. Post-infectious encephalitis tends to be relatively mild, whereas post-infectious encephalomyelitis has a case-fatality rate of up to ten percent. Most cases of mumps deafness affect just one ear and are temporary, but permanent hearing loss occurs in 0.005% of infections. Myocarditis and pericarditis that occur as a result of mumps may lead to endocardial fibroelastosis, i.e. thickening of the endocardium. With extreme rarity, infertility and premature menopause have occurred as a result of mumps oophoritis.




Epidemiology






= Clinical age and immunity

=
Mumps is found worldwide. In the absence of vaccination against mumps there are between 100 and 1,000 cases per 100,000 people each year, i.e. 0.1% to 1.0% of the population are infected each year. The number of cases peaks every 2–5 years, with incidence highest in children 5–9 years old. According to seroconversion surveys done prior to the start of mumps vaccination, a sharp increase in mumps antibody levels at age 2–3 was observed.
Furthermore, 50% of 4–6 year olds, 90% of 14–15 year olds, and 95% of adults had tested positive to prior exposure to mumps, indicating that nearly all people are eventually infected in unvaccinated populations.
Prior to the start of vaccination, mumps accounted for ten percent of meningitis cases and about a third of encephalitis cases. Worldwide, mumps is the most common cause of inflammation of the salivary glands. In children, mumps is the most common cause of deafness in one ear in cases when the inner ear is damaged. Asymptomatic infections are more common in adults, and the rate of asymptomatic infections is very high, up to two-thirds, in vaccinated populations. Mumps vaccination has the effect of increasing the average age of the infected in vaccinated populations that have not previously experienced a mumps outbreak. While infection rates appear to be the same in males and females, males appear to experience symptoms and complications, including neurological involvement, at a higher rate than females. Symptoms are more severe in adolescents and adults than in children.




= Settings of outbreaks

=
It is common for outbreaks of mumps to occur. These outbreaks typically occur in crowded spaces where the virus can spread from person to person easily, such as schools, military barracks, prisons, and sports clubs. Since the introduction of vaccines, the frequency of mumps has declined dramatically, as have complications caused by mumps. The epidemiology in countries that vaccinate reflects the number doses administered, age at vaccination, and vaccination rates. If vaccine coverage is insufficient, then herd immunity may be unobtainable and the average age of infection will increase, leading to an increase in the prevalence of complications. Risk factors include age, exposure to a person with mumps, compromised immunity, time of year, travel history, and vaccination status. Mumps vaccination is less common in developing countries, which consequently have higher rates of mumps.
Cases peak in different seasons of the year in different regions. In temperate climates, cases peak in winter and spring, whereas in tropical regions no seasonality is observed. Additional research has shown that mumps increases in frequency as temperature and humidity increase. The seasonality of mumps is thought to be caused by several factors: fluctuation in the human immune response due to seasonal factors, such as changes in melatonin levels; behavior and lifestyle changes, such as school attendance and indoor crowding; and meteorological factors such as changes in temperature, brightness, wind, and humidity.




References






External links

• Source: MUMPS

MUMPS ("Massachusetts General Hospital Utility Multi-Programming System"), or M, is an imperative, high-level programming language with an integrated transaction processing key–value database. It was originally developed at Massachusetts General Hospital for managing patient medical records and hospital laboratory information systems.
MUMPS technology has since expanded as the predominant database for health information systems and electronic health records in the United States. MUMPS-based information systems, such as Epic Systems', provide health information services for over 78% of patients across the U.S.
A unique feature of the MUMPS technology is its integrated database language, allowing direct, high-speed read-write access to permanent disk storage.




History






= 1960s-1970s - Genesis

=
MUMPS was developed by Neil Pappalardo, Robert A. Greenes, and Curt Marble in Dr. Octo Barnett's lab at the Massachusetts General Hospital (MGH) in Boston during 1966 and 1967. It grew out of frustration, during a National Institutes of Health (NIH)-support hospital information systems project at the MGH, with the development in assembly language on a time-shared PDP-1 by primary contractor Bolt Beranek & Newman, Inc. (BBN). MUMPS came out of an internal "skunkworks" project at MGH by Pappalardo, Greenes, and Marble to create an alternative development environment. As a result of initial demonstration of capabilities, Dr. Barnett's proposal to NIH in 1967 for renewal of the hospital computer project grant took the bold step of proposing that the system be built in MUMPS going forward, rather than relying on the BBN approach. The project was funded, and serious implementation of the system in MUMPS began.
The original MUMPS system was, like Unix a few years later, built on a DEC PDP-7. Octo Barnett and Neil Pappalardo obtained a backward compatible PDP-9, and began using MUMPS in the admissions cycle and laboratory test reporting. MUMPS was then an interpreted language, yet even then, incorporated a hierarchical database file system to standardize interaction with the data and abstract disk operations so they were only done by the MUMPS language itself. MUMPS was also used in its earliest days in an experimental clinical progress note entry system and a radiology report entry system.
Some aspects of MUMPS can be traced from RAND Corporation's JOSS through BBN's TELCOMP and STRINGCOMP. The MUMPS team chose to include portability between machines as a design goal.
An advanced feature of the MUMPS language not widely supported in operating systems or in computer hardware of the era was multitasking. Although time-sharing on mainframe computers was increasingly common in systems such as Multics, most mini-computers did not run parallel programs and threading was not available at all. Even on mainframes, the variant of batch processing where a program was run to completion was the most common implementation for an operating system of multi-programming.
It was a few years until Unix was developed. The lack of memory management hardware also meant that all multi-processing was fraught with the possibility that a memory pointer could change some other process. MUMPS programs do not have a standard way to refer to memory directly at all, in contrast to C language, so since the multitasking was enforced by the language, not by any program written in the language it was impossible to have the risk that existed for other systems.
Dan Brevik's DEC MUMPS-15 system was adapted to a DEC PDP-15, where it lived for some time. It was first installed at Health Data Management Systems of Denver in May 1971. The portability proved to be useful and MUMPS was awarded a government research grant, and so MUMPS was released to the public domain which was a requirement for grants. MUMPS was soon ported to a number of other systems including the popular DEC PDP-8, the Data General Nova and on DEC PDP-11 and the Artronix PC12 minicomputer. Word about MUMPS spread mostly through the medical community, and was in widespread use, often being locally modified for their own needs.
Versions of the MUMPS system were rewritten by technical leaders Dennis "Dan" Brevik and Paul Stylos of DEC in 1970 and 1971. By the early 1970s, there were many and varied implementations of MUMPS on a range of hardware platforms. Another noteworthy platform was Paul Stylos' DEC MUMPS-11 on the PDP-11, and MEDITECH's MIIS. In the Fall of 1972, many MUMPS users attended a conference in Boston which standardized the then-fractured language, and created the MUMPS Users Group and MUMPS Development Committee (MDC) to do so. These efforts proved successful; a standard was complete by 1974, and was approved, on September 15, 1977, as ANSI standard, X11.1-1977. At about the same time DEC launched DSM-11 (Digital Standard MUMPS) for the PDP-11. This quickly dominated the market, and became the reference implementation of the time. Also, InterSystems sold ISM-11 for the PDP-11 (which was identical to DSM-11).




= 1980s

=
During the early 1980s several vendors brought MUMPS-based platforms that met the ANSI standard to market. The most significant were:

Digital Equipment Corporation with DSM (Digital Standard MUMPS). For the PDP-11 series DSM-11 was released 1977. VAX DSM was sold in parallel after released 1978. Both hardware families as well as MUMPS versions were available until 1995 from DEC. The DSM-11 was ported to the Alpha in two variants: DSM for OpenVMS, and as DSM for Ultrix.
InterSystems with ISM (InterSystems M) on VMS (M/VX), ISM-11 later M/11+ on the PDP-11 platform (1978), M/PC on MS-DOS, M/DG on Data General, M/VM on IBM VM/CMS, and M/UX on various Unixes.
Greystone Technology Corporation founded 1980, with a compiled version called GT.M for AIX, HP-UX, UNIX and OpenVMS
DataTree Inc. with an Intel PC-based product called DTM. (1982)
Micronetics Design Corporation (1980) with a product line called MSM. MSM-PC, MSM/386, MS-UNIX, MSM-NT, MSM/VM fo IBM, VAX/VMS platforms and OpenVMS Alpha platforms.
Computer Consultants (later renamed MGlobal), a Houston-based company originally created CCSM on 6800, then 6809, and eventually a port to the 68000, which later became MacMUMPS, a Mac OS-based product. They also worked on the MGM MUMPS implementation. MGlobal also ported their implementation to the DOS platform. MGlobal MUMPS was the first commercial MUMPS for the IBM PC and the only implementation for the classic Mac OS.
Tandem Computers developed an implementation for their fault-tolerant computers.
IBM briefly sold a MUMPS implementation named MUMPS/VM which ran as a virtual machine on top of VM/370.
This period also saw considerable MDC activity. The second revision of the ANSI standard for MUMPS (X11.1-1984) was approved on November 15, 1984.




= 1990s

=
On November 11, 1990, the third revision of the ANSI standard (X11.1-1990) was approved.
In 1992 the same standard was also adopted as ISO standard 11756–1992. Use of M as an alternative name for the language was approved around the same time.
On December 8, 1995, the fourth revision of the standard (X11.1-1995) was approved by ANSI, and by ISO in 1999 as ISO 11756:1999, which was also published by ANSI. The MDC finalized a further revision to the standard in 1998 but this has not been presented to ANSI for approval.
In 1999 the last M Standard (ISO-IEC 11756-1999) was approved. ISO re-affirmed this on 2020. Together with ISO/IEC 15851:1999, Open MUMPS Interconnect and ISO/IEC 15852:1999, MUMPS Windowing Application Programmers Interface.




= 2000s

=
By 1998, the middleware vendor InterSystems had become the dominant player in the MUMPS market with the purchase of several other vendors. Initially they acquired DataTree Inc. in 1993. On December 30, 1994, InterSystems acquired the DSM product line from DEC. InterSystems consolidated these products into a single product line, branding them, on several hardware platforms, as OpenM. In 1997, InterSystems launched a new product named Caché. This was based on their ISM product, but with influences from the other implementations. Micronetics Design Corporation, at this time #2 on the market, was acquired by InterSystems on June 21, 1998. InterSystems remains the dominant "M vendor" owning MSM, DSM, ISM, DTM and selling its IRIS Data Platform (and, until 2018, its predecessor Caché) to M developers who write applications for a variety of operating systems. Also Intersystems did not use the term M anymore, neither followed the M standard.
Greystone Technology Corporation's GT.M implementation was sold to Sanchez Computer Associates (now part of FIS) in the mid-1990s. On November 7, 2000, Sanchez made GT.M for Linux available under the GPL license and on October 28, 2005, GT.M for OpenVMS and Tru64 UNIX were also made available under the AGPL license. GT.M continues to be available on other UNIX platforms under a traditional license.
During 2000, Ray Newman and others released MUMPS V1, an implementation of MUMPS (initially on FreeBSD) similar to DSM-11. MUMPS V1 has since been ported to Linux, Mac OS X, and Windows (using cygwin). Initially only for the x86 CPU, MUMPS V1 has now been ported to the Raspberry Pi.
Released in April 2002 an MSM derivative called M21 is offered from the Real Software Company of Rugby, UK.
There are also several open source implementations of MUMPS, including some research projects. The most notable of these is Mumps/II, by Dr. Kevin O'Kane (Professor Emeritus, University of Northern Iowa) and students' project. Dr. O'Kane has also ported the interpreter to Mac OS X.
One of the original creators of the MUMPS language, Neil Pappalardo, founded a company called MEDITECH in 1969. They extended and built on the MUMPS language, naming the new language MIIS (and later, another language named MAGIC). Unlike InterSystems, MEDITECH no longer sells middleware, so MIIS and MAGIC are now only used internally at MEDITECH.
New on the market since 2022 is MiniM from Eugene Karataev




= Name

=
The chief executive of InterSystems disliked the name MUMPS and felt that it represented a serious marketing obstacle. Thus, favoring M to some extent became identified as alignment with InterSystems. The 1990 ANSI Standard was open to both M and MUMPS and after a "world-wide" discussion in 1992 the Mumps User Groups officially changed the name to M. The dispute also reflected rivalry between organizations (the M Technology Association, the MUMPS Development Committee, the ANSI and ISO Standards Committees) as to who determines the "official" name of the language.
As of 2020, the ISO still mentions both M and MUMPS as officially accepted names.
Massachusetts General Hospital registered "MUMPS" as a trademark with the USPTO on November 28, 1971, and renewed it on November 16, 1992, but let it expire on August 30, 2003.




Design






= Overview

=
MUMPS is a language intended for and designed to build database applications. Secondary language features were included to help programmers make applications using minimal computing resources. The original implementations were interpreted, though modern implementations may be fully or partially compiled. Individual "programs" run in memory "partitions". Early MUMPS memory partitions were limited to 2048 bytes so aggressive abbreviation greatly aided multi-programming on severely resource limited hardware, because more than one MUMPS job could fit into the very small memories extant in hardware at the time. The ability to provide multi-user systems was another language design feature. The word "Multi-Programming" in the acronym points to this. Even the earliest machines running MUMPS supported multiple jobs running at the same time. With the change from mini-computers to micro-computers a few years later, even a "single user PC" with a single 8-bit CPU and 16K or 64K of memory could support multiple users, who could connect to it from (non-graphical) video display terminals.
Since memory was tight originally, the language design for MUMPS valued very terse code. Thus, every MUMPS command or function name could be abbreviated from one to three letters in length, e.g. Quit (exit program) as Q, $P = $Piece function, R = Read command, $TR = $Translate function. Spaces and end-of-line markers are significant in MUMPS because line scope promoted the same terse language design. Thus, a single line of program code could express, with few characters, an idea for which other programming languages could require 5 to 10 times as many characters. Abbreviation was a common feature of languages designed in this period (e.g., FOCAL-69, early BASICs such as Tiny BASIC, etc.). An unfortunate side effect of this, coupled with the early need to write minimalist code, was that MUMPS programmers routinely did not comment code and used extensive abbreviations. This meant that even an expert MUMPS programmer could not just skim through a page of code to see its function but would have to analyze it line by line.
Database interaction is transparently built into the language. The MUMPS language provides a hierarchical database made up of persistent sparse arrays, which is implicitly "opened" for every MUMPS application. All variable names prefixed with the caret character (^) use permanent (instead of RAM) storage, will maintain their values after the application exits, and will be visible to (and modifiable by) other running applications. Variables using this shared and permanent storage are called Globals in MUMPS, because the scoping of these variables is "globally available" to all jobs on the system. The more recent and more common use of the name "global variables" in other languages is a more limited scoping of names, coming from the fact that unscoped variables are "globally" available to any programs running in the same process, but not shared among multiple processes. The MUMPS Storage mode (i.e. globals stored as persistent sparse arrays), gives the MUMPS database the characteristics of a document-oriented database.
All variable names which are not prefixed with caret character (^) are temporary and private. Like global variables, they also have a hierarchical storage model, but are only "locally available" to a single job, thus they are called "locals". Both "globals" and "locals" can have child nodes (called subscripts in MUMPS terminology). Subscripts are not limited to numerals—any ASCII character or group of characters can be a subscript identifier. While this is not uncommon for modern languages such as Perl or JavaScript, it was a highly unusual feature in the late 1970s. This capability was not universally implemented in MUMPS systems before the 1984 ANSI standard, as only canonically numeric subscripts were required by the standard to be allowed. Thus, the variable named 'Car' can have subscripts "Door", "Steering Wheel", and "Engine", each of which can contain a value and have subscripts of their own. The variable ^Car("Door") could have a nested variable subscript of "Color" for example. Thus, you could say

to modify a nested child node of ^Car. In MUMPS terms, "Color" is the 2nd subscript of the variable ^Car (both the names of the child-nodes and the child-nodes themselves are likewise called subscripts). Hierarchical variables are similar to objects with properties in many object-oriented languages. Additionally, the MUMPS language design requires that all subscripts of variables are automatically kept in sorted order. Numeric subscripts (including floating-point numbers) are stored from lowest to highest. All non-numeric subscripts are stored in alphabetical order following the numbers. In MUMPS terminology, this is canonical order. By using only non-negative integer subscripts, the MUMPS programmer can emulate the arrays data type from other languages. Although MUMPS does not natively offer a full set of DBMS features such as mandatory schemas, several DBMS systems have been built on top of it that provide application developers with flat-file, relational, and network database features.
Additionally, there are built-in operators which treat a delimited string (e.g., comma-separated values) as an array. Early MUMPS programmers would often store a structure of related information as a delimited string, parsing it after it was read in; this saved disk access time and offered considerable speed advantages on some hardware.
MUMPS has no data types. Numbers can be treated as strings of digits, or strings can be treated as numbers by numeric operators (coerced, in MUMPS terminology). Coercion can have some odd side effects, however. For example, when a string is coerced, the parser turns as much of the string (starting from the left) into a number as it can, then discards the rest. Thus the statement IF 20<"30 DUCKS" is evaluated as TRUE in MUMPS.
Other features of the language are intended to help MUMPS applications interact with each other in a multi-user environment. Database locks, process identifiers, and atomicity of database update transactions are all required of standard MUMPS implementations.
In contrast to languages in the C or Wirth traditions, some space characters between MUMPS statements are significant. A single space separates a command from its argument, and a space, or newline, separates each argument from the next MUMPS token. Commands which take no arguments (e.g., ELSE) require two following spaces. The concept is that one space separates the command from the (nonexistent) argument, the next separates the "argument" from the next command. Newlines are also significant; an IF, ELSE or FOR command processes (or skips) everything else till the end-of-line. To make those statements control multiple lines, you must use the DO command to create a code block.




= Hello, World! example

=
A simple "Hello, World!" program in MUMPS might be:

and would be run with the command do ^hello after it has been saved to disk. For direct execution of the code a kind of "label" (any alphanumeric string) on the first position of the program line is needed to tell the mumps interpreter where to start execution. Since MUMPS allows commands to be strung together on the same line, and since commands can be abbreviated to a single letter, this routine could be made more compact:

The ',!' after the text generates a newline. This code would return to the prompt.




= Features

=
ANSI X11.1-1995 gives a complete, formal description of the language; an annotated version of this standard is available online.
Language features include:

Data types
There is one universal data type, which is implicitly coerced to string, integer, or floating-point data types as context requires.
Booleans (called truthvalues in MUMPS)
In IF commands and other syntax that has expressions evaluated as conditions, any string value is evaluated as a numeric value and, if that is a nonzero value, then it is interpreted as True. a Declarations
None. All variables are dynamically created at the first time a value is assigned.
Lines
are important syntactic entities, unlike their status in languages patterned on C or Pascal. Multiple statements per line are allowed and are common. The scope of any IF, ELSE, and FOR command is "the remainder of current line."
Case sensitivity
Commands and intrinsic functions are case-insensitive. In contrast, variable names and labels are case-sensitive. There is no special meaning for upper vs. lower-case and few widely followed conventions. The percent sign (%) is legal as first character of variables and labels.
Postconditionals
execution of almost any command can be controlled by following it with a colon and a truthvalue expression. SET:N<10 A="FOO" sets A to "FOO" if N is less than 10; DO:N>100 PRINTERR, performs PRINTERR if N is greater than 100. This construct provides a conditional whose scope is less than a full line.
Abbreviation
You can abbreviate nearly all commands and native functions to one, two, or three characters.
Reserved words
None. Since MUMPS interprets source code by context, there is no need for reserved words. You may use the names of language commands as variables, so the following is perfectly legal MUMPS code:

MUMPS can be made more obfuscated by using the contracted operator syntax, as shown in this terse example derived from the example above:

Arrays
are created dynamically, stored as B-trees, are sparse (i.e. use almost no space for missing nodes), can use any number of subscripts, and subscripts can be strings or numeric (including floating point). Arrays are always automatically stored in sorted order, so there is never any occasion to sort, pack, reorder, or otherwise reorganize the database. Built-in functions such as $DATA, $ORDER, $NEXT(deprecated), and $QUERY functions provide efficient examination and traversal of the fundamental array structure, on disk or in memory.

Local arrays
variable names not beginning with caret (i.e. "^") are stored in memory by process, are private to the creating process, and expire when the creating process terminates. The available storage depends on implementation. For those implementations using partitions, it is limited to the partition size (a small partition might be 32K). For other implementations, it may be several megabytes.
Global arrays
^abc, ^def. These are stored on disk, are available to all processes, and are persistent when the creating process terminates. Very large globals (for example, hundreds of gigabytes) are practical and efficient in most implementations. This is MUMPS' main "database" mechanism. It is used instead of calling on the operating system to create, write, and read files.
Indirection
in many contexts, @VBL can be used, and effectively substitutes the contents of VBL into another MUMPS statement. SET XYZ="ABC" SET @XYZ=123 sets the variable ABC to 123. SET SUBROU="REPORT" DO @SUBROU performs the subroutine named REPORT. This substitution allows for lazy evaluation and late binding as well as effectively the operational equivalent of "pointers" in other languages.
Piece function
This breaks variables into segmented pieces guided by a user specified separator string (sometimes called a "delimiter"). Those who know awk will find this familiar. $PIECE(STRINGVAR,"^",3) means the "third caret-separated piece of STRINGVAR." The piece function can also appear as an assignment (SET command) target.
$PIECE("world.std.com",".",2) yields std.
After

SET $P(X,"@",1)="office" causes X to become "office@world.std.com" (note that $P is equivalent to $PIECE and could be written as such).
Order function
This function treats its input as a structure, and finds the next index that exists which has the same structure except for the last subscript. It returns the sorted value that is ordered after the one given as input. (This treats the array reference as a content-addressable data rather than an address of a value.)

$Order(stuff("")) yields 6, $Order(stuff(6)) yields 10, $Order(stuff(8)) yields 10, $Order(stuff(10)) yields 15, $Order(stuff(15)) yields "".

Here, the argument-less For repeats until stopped by a terminating Quit. This line prints a table of i and stuff(i) where i is successively 6, 10, and 15.
For iterating the database, the Order function returns the next key to use.

MUMPS supports multiple simultaneous users and processes even when the underlying operating system does not (e.g., MS-DOS). Additionally, there is the ability to specify an environment for a variable, such as by specifying a machine name in a variable (as in SET ^|"DENVER"|A(1000)="Foo"), which can allow you to access data on remote machines.




= Criticism

=

Some aspects of MUMPS syntax differ strongly from that of more modern languages, which can cause confusion, although those aspects vary between different versions of the language. On some versions, whitespace is not allowed within expressions, as it ends a statement: 2 + 3 is an error, and must be written 2+3. All operators have the same precedence and are left-associative (2+3*10 evaluates to 50). The operators for "less than or equal to" and "greater than or equal to" are '> and '< (that is, the Boolean negation operator ' plus a strict comparison operator in the opposite direction), although some versions allow the use of the more standard <= and >= respectively. Periods (.) are used to indent the lines in a DO block, not whitespace. The ELSE command does not need a corresponding IF, as it operates by inspecting the value in the built-in system variable $test.
MUMPS scoping rules are more permissive than other modern languages. Declared local variables are scoped using the stack. A routine can normally see all declared locals of the routines below it on the call stack, and routines cannot prevent routines they call from modifying their declared locals, unless the caller manually creates a new stack level (do) and aliases each of the variables they wish to protect (. new x,y) before calling any child routines. By contrast, undeclared variables (variables created by using them, rather than declaration) are in scope for all routines running in the same process, and remain in scope until the program exits.
Because MUMPS database references differ from internal variable references only in the caret prefix, it is dangerously easy to unintentionally edit the database, or even to delete a database "table".




Users


The US Department of Veterans Affairs (formerly the Veterans Administration) was one of the earliest major adopters of the MUMPS language. Their development work (and subsequent contributions to the free MUMPS application codebase) was an influence on many medical users worldwide. In 1995, the Veterans Affairs' patient Admission/Tracking/Discharge system, Decentralized Hospital Computer Program (DHCP) was the recipient of the Computerworld Smithsonian Award for best use of Information Technology in Medicine. In July 2006, the Department of Veterans Affairs (VA) / Veterans Health Administration (VHA) was the recipient of the Innovations in American Government Award presented by the Ash Institute of the John F. Kennedy School of Government at Harvard University for its extension of DHCP into the Veterans Health Information Systems and Technology Architecture (VistA). Nearly the entire VA hospital system in the United States, the Indian Health Service, and major parts of the Department of Defense CHCS hospital system use MUMPS databases for clinical data tracking.
Other healthcare IT companies using MUMPS include:

Epic
MEDITECH
GE Healthcare (formerly IDX Systems and Centricity)
AmeriPath (part of Quest Diagnostics)
Care Centric
Allscripts
Coventry Health Care
EMIS Health
Sunquest Information Systems (formerly Misys Healthcare).
Netsmart
Many reference laboratories, such as DASA, Quest Diagnostics, and Dynacare, use MUMPS software written by or based on Antrim Corporation code. Antrim was purchased by Misys Healthcare (now Sunquest Information Systems) in 2001.
MUMPS is also widely used in financial applications. MUMPS gained an early following in the financial sector and is in use at many banks and credit unions. It is used by the Bank of England and Barclays Bank.




Implementations


Since 2005, the most popular implementations of MUMPS have been Greystone Technology MUMPS (GT.M) from Fidelity National Information Services, and Caché, from Intersystems Corporation. The European Space Agency announced on May 13, 2010, that it will use the InterSystems Caché database to support the Gaia mission. This mission aims to map the Milky Way with unprecedented precision. InterSystems is in the process of phasing out Caché in favor of Iris.
Other current implementations include:

M21
YottaDB
MiniM
Reference Standard M
FreeM




See also


Profile Scripting Language
Caché ObjectScript
GT.M
InterSystems Caché




References






Further reading






External links


Trask, Gardner; Diamond, Jon (6 April 1999). "M Technology and MUMPS Language FAQ, Part 1/2". Newsgroup: comp.lang.mumps. Usenet: FKu0LK.19p@world.std.com. Retrieved 25 October 2022.
"comp.lang.mumps". Newsgroup: comp.lang.mumps. Retrieved 25 October 2022 – via Google Groups.
Mumps Programming Language Interpreter (GPL) by Kevin O'Kane, University of Northern Iowa
MUMPS on SourceForge
M Links at Hardhats.org
Development and Operation of a MUMPS Laboratory Information System: A Decade's Experience at Johns Hopkins Hospital
IDEA Systems' technology solutions based on YottaDB (formerly FIS GT.M) and Caché
MUMPS documentation, topics, and resources (mixed Czech and English)

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