Measles is a highly infectious illness caused by the rubeola virus.
However, if measles enters an area where the people have never been exposed, the result can be devastating.
Vaccination prevents many cases of measles around the world. The World Health Organization (WHO) estimate that 2.6 million people who have not had the vaccine die of measles every year.
Fast facts on measles
Here are some key points about measles. More detail is in the main article.
Measles is a highly infectious condition
Scientists have identified 21 strains of the measles virus
Symptoms of measles can include watery eyes, sneezing, and a dry hacking cough
There is no specific treatment for measles. Prevention is better than cure
Pregnant women should not take the vaccine
What is measles?
Measles is a viral disease that can spread rapidly.
Also known as rubeola or morbilli, measles is an endemic disease, meaning it is continually present in a community, and many people develop resistance.
It is an unpleasant condition but one that normally passes without treatment within 7 to 10 days.
After a bout of measles, a person gains immunity for the rest of their life. They are very unlikely to contract measles a second time.
Measles is often noticed through a breakout of spots.
The symptoms of measles always include fever and at least one of the three Cs:
coryza, or runny nose
Symptoms will appear about 9 to 11 days after initial infection.
Symptoms may include:
dry hacking cough
conjunctivitis, or swollen eyelids and inflamed eyes
photophobia, or sensitivity to light
a reddish-brown rash
Koplik’s spots, or very small grayish-white spots with bluish-white centers in the mouth, insides of cheeks, and throat
generalized body aches
There is often a fever. This can range from mild severe, up to 40.6 degrees Centigrade. It can last several days, and it may fall and then rise again when the rash appears.
The reddish-brown rash appears around 3 to 4 days after initial symptoms. This can last for over a week.
The rash usually starts behind the ears and spreads over the head and neck. After a couple of days, it spreads to the rest of the body, including the legs. As the spots grow, they often join together.
Most childhood rashes are not measles, but a child should see a doctor if:
a parent suspects the child may have measles
symptoms do not improve, or they get worse
the fever rises to above 38º Centigrade (ºC) or 100.4º Fahrenheit (ºF)
other symptoms resolve, but the fever persists
The measles vaccine is widely available and is said to have dropped global rates of measles by over 75 percent.
Complications from measles are fairly common. Some can be serious.
People most at risk are patients with a weak immune system, such as those with HIV, AIDS, leukemia, or a vitamin deficiency, very young children, and adults over the age of 20 years.
Older people are more likely to have complications than healthy children over the age of 5 years.
Complications can include:
respiratory tract infections, such as laryngitis and bronchitis
ear infections, which can lead to permanent hearing loss
Patients with a weakened immune system who have measles are more susceptible to bacterial pneumonia. This can be fatal if not treated.
The following less common complications are also possible:
Hepatitis: Liver complications can occur in adults and in children who are taking some medications.
Encephalitis: This affects around 1 in every 1,000 patients with measles. It is an inflammation of the brain that can sometimes be fatal. It may occur soon after measles, or several years later.
Thrombocytopenia, or low platelet count, affects the blood’s ability to clot. The patient may bruise easily.
Squint: Eye nerves and eye muscles may be affected.
Complications that are very rare but possible include:
Neuritis, an infection of the optic nerve that can lead to vision loss
Subacute sclerosing panencephalitis (SSPE): A brain disease that can affect 2 in every 100,000 people, months or years after measles infection. Convulsions, motor abnormalities, cognitive issues, and death can occur.
Other nervous system complications include toxic encephalopathy, retrobulbar neuritis, transverse myelitis, and ascending myelitis.
Measles during pregnancy can lead to miscarriage, early delivery, or low birth weight. A woman who is planning to become pregnant and has not been vaccinated should ask her doctor for advice.
There are two types of measles:
Measles: This is the standard form caused by the rubeola virus.
Rubella, or German measles: This is caused by the rubella virus.
Rubella generally presents as mild but presents more of a risk to unborn infants than young children if a woman contracts the virus while she is pregnant.
It is neither as infectious nor as severe as standard measles.