Measles also known as Rubeola, is an infection of the respiratory system caused by a virus, specifically a paramyxovirus of the genus Morbillivirus. Morbilliviruses, like other paramyxoviruses, are enveloped, single-stranded, negative-sense RNA viruses. Symptoms include fever, cough, runny nose, red eyes and a generalized, maculopapular, erythematous rash.
Measles is spread through respiration (contact with fluids from an infected person's nose and mouth, either directly or through aerosol transmission), and is highly contagious—90% of people without immunity sharing living space with an infected person will catch it.
An asymptomatic incubation period occurs nine to twelve days from initial exposure. The period of infectivity has not been definitively established, some saying it lasts from two to four days prior, until two to five days following the onset of the rash (i.e. four to nine days infectivity in total), whereas others say it lasts from two to four days prior until the complete disappearance of the rash.
There is no specific treatment for measles. Most patients with uncomplicated measles will recover with rest and supportive treatment.
It is, however, important to seek medical advice if the patient becomes more unwell, as they may be developing complications.
For the vast majority of healthy patients, measles is not serious; though in some cases complications may occur, which may include bronchitis, acute encephalitis and – very rarely – panencephalitis, which is usually or always fatal.
Skin of a patient after 3 days of measles infection.
Presentation of “Koplik's spots” on the third pre-eruptive day, indicative of the beginning onset of measles.
The classical signs and symptoms of measles include four-day fevers [ the 4 D's ] and the three Cs — cough, coryza (head cold), and conjunctivitis (red eyes) — along with fever, anorexia, and rashes.
The fever may reach up to 40 °C (104 °F). Koplik's spots seen inside the mouth are pathognomonic (diagnostic) for measles, but are not often seen, even in real cases of measles, because they are transient and may disappear within a day of arising.
The characteristic measles rash is classically described as a generalized, maculopapular, erythematous rash that begins several days after the fever starts.
It starts on the back of the ears and, after a few hours, spreads to the head and neck before spreading to cover most of the body, often causing itching.
The measles rash appears two to four days after the initial symptoms and lasts for up to eight days. The rash is said to "stain", changing color from red to dark brown, before disappearing.
Between the years 1987 and 2000, the case fatality rate across the United States was 3 measles-attributable deaths per 1000 cases, or 0.3%.
In underdeveloped nations with high rates of malnutrition and poor healthcare, fatality rates have been as high as 28%. In immunocompromised patients (e.g. people with AIDS) the fatality rate is approximately 30%.
Measles is caused by the measles virus, a single-stranded, negative-sense, enveloped RNA virus of the genus Morbillivirus within the family Paramyxoviridae. Humans are the natural hosts of the virus; no animal reservoirs are known to exist. This highly contagious virus is spread by coughing and sneezing via close personal contact or direct contact with secretions.
Risk factors for measles virus infection include the following:
Alternatively, laboratory diagnosis of measles can be done with confirmation of positive measles IgM antibodies or isolation of measles virus RNA from respiratory specimens.
In patients where phlebotomy is not possible, saliva can be collected for salivary measles-specific IgA testing.
Positive contact with other patients known to have measles adds strong epidemiological evidence to the diagnosis.
The contact with any infected person in any way, including semen through sex, saliva, or mucus, can cause infection.
Rates of measles vaccination worldwide
Measles cases reported in the United States.
In developed countries, most children are immunized against measles by the age of 18 months, generally as part of a three-part MMR vaccine (measles, mumps, and rubella).
The vaccination is generally not given earlier than this because sufficient of the antimeasles immunoglobulins (antibodies) acquired via the placenta from the mother during pregnancy may persist to prevent the vaccine viruses from being effective.
A second dose is usually given to children between the ages of four and five, to increase rates of immunity. Vaccination rates have been high enough to make measles relatively uncommon.
Even a single case in a college dormitory or similar setting is often met with a local vaccination program, in case any of the people exposed are not already immune.
Adverse reactions to vaccination are rare, with fever and pain at the injection site being the most common. Life threatening adverse reactions occur in less than one per million vaccinations.
In developing countries where measles is highly endemic, WHO doctors recommend two doses of vaccine be given at six and nine months of age.
Measles is spread through respiration (contact with fluids from an infected person's nose and mouth, either directly or through aerosol transmission), and is highly contagious—90% of people without immunity sharing living space with an infected person will catch it.
An asymptomatic incubation period occurs nine to twelve days from initial exposure. The period of infectivity has not been definitively established, some saying it lasts from two to four days prior, until two to five days following the onset of the rash (i.e. four to nine days infectivity in total), whereas others say it lasts from two to four days prior until the complete disappearance of the rash.
There is no specific treatment for measles. Most patients with uncomplicated measles will recover with rest and supportive treatment.
It is, however, important to seek medical advice if the patient becomes more unwell, as they may be developing complications.
For the vast majority of healthy patients, measles is not serious; though in some cases complications may occur, which may include bronchitis, acute encephalitis and – very rarely – panencephalitis, which is usually or always fatal.
Signs and symptoms
The fever may reach up to 40 °C (104 °F). Koplik's spots seen inside the mouth are pathognomonic (diagnostic) for measles, but are not often seen, even in real cases of measles, because they are transient and may disappear within a day of arising.
The characteristic measles rash is classically described as a generalized, maculopapular, erythematous rash that begins several days after the fever starts.
It starts on the back of the ears and, after a few hours, spreads to the head and neck before spreading to cover most of the body, often causing itching.
The measles rash appears two to four days after the initial symptoms and lasts for up to eight days. The rash is said to "stain", changing color from red to dark brown, before disappearing.
Complications
Complications with measles are relatively common, ranging from the relatively mild and less serious ones like diarrhea to more serious ones such as pneumonia, otitis media, acute encephalitis (and very rarely SSPE – subacute sclerosing panencephalitis), and corneal ulceration (leading to corneal scarring). Complications are usually more severe in adults who catch the virus. The death rate in the 1920s was around 30% for measles pneumonia.Between the years 1987 and 2000, the case fatality rate across the United States was 3 measles-attributable deaths per 1000 cases, or 0.3%.
In underdeveloped nations with high rates of malnutrition and poor healthcare, fatality rates have been as high as 28%. In immunocompromised patients (e.g. people with AIDS) the fatality rate is approximately 30%.
Causes
| Measles | |
|---|---|
 |
|
| Measles virus electron micrograph | |
| Virus classification | |
| Group: | Group V ((-)ssRNA) |
| Order: | Mononegavirales |
| Family: | Paramyxoviridae |
| Subfamily: | Paramyxovirinae |
| Genus: | Morbillivirus |
Measles is caused by the measles virus, a single-stranded, negative-sense, enveloped RNA virus of the genus Morbillivirus within the family Paramyxoviridae. Humans are the natural hosts of the virus; no animal reservoirs are known to exist. This highly contagious virus is spread by coughing and sneezing via close personal contact or direct contact with secretions.
Risk factors for measles virus infection include the following:
- Children with immunodeficiency due to HIV or AIDS, leukemia, alkylating agents, or corticosteroid therapy, regardless of immunization status
- Travel to areas where measles is endemic or contact with travelers to endemic areas
- Infants who lose passive antibody before the age of routine immunization
- Malnutrition
- Underlying immunodeficiency
- Pregnancy
- Vitamin A deficiency
Diagnosis
Clinical diagnosis of measles requires a history of fever of at least three days, with at least one of the three C's (cough, coryza, conjunctivitis). Observation of Koplik's spots is also diagnostic of measles.Alternatively, laboratory diagnosis of measles can be done with confirmation of positive measles IgM antibodies or isolation of measles virus RNA from respiratory specimens.
In patients where phlebotomy is not possible, saliva can be collected for salivary measles-specific IgA testing.
Positive contact with other patients known to have measles adds strong epidemiological evidence to the diagnosis.
The contact with any infected person in any way, including semen through sex, saliva, or mucus, can cause infection.
Prevention
The vaccination is generally not given earlier than this because sufficient of the antimeasles immunoglobulins (antibodies) acquired via the placenta from the mother during pregnancy may persist to prevent the vaccine viruses from being effective.
A second dose is usually given to children between the ages of four and five, to increase rates of immunity. Vaccination rates have been high enough to make measles relatively uncommon.
Even a single case in a college dormitory or similar setting is often met with a local vaccination program, in case any of the people exposed are not already immune.
Adverse reactions to vaccination are rare, with fever and pain at the injection site being the most common. Life threatening adverse reactions occur in less than one per million vaccinations.
The vaccine should be given whether the child is HIV-infected or not. The vaccine is less effective in HIV-infected infants than in the general population, but early treatment with antiretroviral drugs can increase its effectiveness.
Measles vaccination programs are often used to deliver other child health interventions, as well, such as bed nets to protect against malaria, antiparasite medicine and vitamin A supplements, and so contribute to the reduction of child deaths from other causes.
Unvaccinated populations are at risk for the disease. Traditionally low vaccination rates in northern Nigeria dropped further in the early 2000s when radical preachers promoted a rumor that polio vaccines were a Western plot to sterilize Muslims and infect them with HIV.
The number of cases of measles rose significantly, and hundreds of children died. This could also have had to do with the aforementioned other health-promoting measures often given with the vaccine.
Claims of a connection between the MMR vaccine and autism were raised in a 1998 paper in The Lancet, a respected British medical journal.
Later investigation by Sunday Times journalist Brian Deer discovered the lead author of the article, Andrew Wakefield, had multiple undeclared conflicts of interest, and had broken other ethical codes. The Lancet paper was later retracted, and Wakefield was found guilty by the General Medical Council of serious professional misconduct in May 2010, and was struck off the Medical Register, meaning he could no longer practise as a doctor in the UK.
The GMC's panel also considered two of Wakefield's colleagues: John Walker-Smith was also found guilty and struck off the Register; Simon Murch "was in error" but acted in good faith, and was cleared.
Walker-Smith was later cleared and reinstated after winning an appeal; the appeal court's finding was based on the panel's conduct of the case, and gave no support to the MMR-autism hypothesis, which the official judgement described as lacking support from any respectable body of opinion.
The research was declared fraudulent in 2011 by the BMJ. Scientific evidence provides no support for the hypothesis that MMR plays a role in causing autism.
The autism-related MMR study in Britain caused use of the vaccine to plunge, and measles cases came back: 2007 saw 971 cases in England and Wales, the biggest rise in occurrence in measles cases since records began in 1995.
A 2005 measles outbreak in Indiana was attributed to children whose parents refused vaccination, as was another outbreak in 2008 in San Diego.
Treatment
There is no specific treatment for measles. Most patients with uncomplicated measles will recover with rest and supportive treatment. It is, however, important to seek medical advice if the patient becomes more unwell, as they may be developing complications.Some patients will develop pneumonia as a sequelae to the measles. Other complications include ear infections, bronchitis, and encephalitis.
Acute measles encephalitis has a mortality rate of 15%. While there is no specific treatment for measles encephalitis, antibiotics are required for bacterial pneumonia, sinusitis, and bronchitis that can follow measles.
All other treatment addresses symptoms, with ibuprofen, or acetaminophen (paracetamol) to reduce fever and pain and, if required, a fast-acting bronchodilator for cough.
As for aspirin, some research has suggested a correlation between children who take aspirin and the development of Reye's syndrome.
Some research has shown aspirin may not be the only medication associated with Reye's, and even antiemetics have been implicated, with the point being the link between aspirin use in children and Reye's syndrome development is weak at best, if not actually nonexistent.
Nevertheless, most health authorities still caution against the use of aspirin for any fevers in children under 16.
The use of vitamin A in treatment has been investigated. A systematic review of trials into its use found no significant reduction in overall mortality, but it did reduce mortality in children aged under two years.
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