Measles is a respiratory disease caused by a virus. The disease of measles and the virus that causes it share the same name. The disease is also called rubeola. Measles virus normally grows in the cells that line the back of the throat and lungs.
The symptoms of measles generally begin about 7-14 days after a person is infected, and include:
- Blotchy rash
- Runny nose
- Red, watery eyes (conjunctivitis)
- Feeling run down, achy (malaise)
- Tiny white spots with bluish-white centers found inside the mouth(Koplik's spots)
A typical case of measles begins with mild to moderate fever, cough, runny nose, red eyes, and sore throat. Two or three days after symptoms begin, tiny white spots (Koplik's spots) may appear inside the mouth.
Three to five days after the start of symptoms, a red or reddish-brown rash appears. The rash usually begins on a person's face at the hairline and spreads downward to the neck, trunk, arms, legs, and feet. When the rash appears, a person's fever may spike to more than 104 degrees Fahrenheit.
After a few days, the fever subsides and the rash fades.
About one out of 10 children with measles also gets an ear infection, and up to one out of 20 gets pneumonia. About one out of 1,000 gets encephalitis, and one or two out of 1,000 die. Other rash-causing diseases often confused with measles include roseola (roseola infantum) and rubella (German measles).
While measles is almost gone from the United States, it still kills nearly 200,000 people each year around the world. Measles can also make a pregnant woman have a miscarriage or give birth prematurely.
Measles spreads through the air by breathing, coughing or sneezing. It is so contagious that any child who is exposed to it and is not immune will probably get the disease.
Measles is very rare in countries and regions of the world that are able to keep vaccination coverage high. In North and South America, Finland, and some other areas, endemic measles transmission is considered to have been interrupted through vaccination. There are still sporadic cases of measles in the United States because visitors from other countries or US citizens traveling abroad can become infected before or during travel and spread the infection to unvaccinated or unprotected persons.
Worldwide, there are estimated to be 20 million cases and 164,000 deaths each year. More than half of the deaths occur in India.
One of the earliest written descriptions of measles as a disease was provided by an Arab physician in the 9th century who described differences between measles and smallpox in his medical notes.
A Scottish physician, Francis Home, demonstrated in 1757 that measles was caused by an infectious agent present in the blood of patients. In 1954 the virus that causes measles was isolated in Boston, Massachusetts, by John F. Enders and Thomas C. Peebles. Before measles vaccine, nearly all children got measles by the time they were 15 years of age. Each year in the United States about 450 people died because of measles, 48,000 were hospitalized, 7,000 had seizures, and about 1,000 suffered permanent brain damage or deafness. Today there are only about 50 cases a year reported in the United States, and most of these originate outside the country.