measles or rubeola, highly contagious disease of young children, caused by a filterable virus and spread by droplet spray from the nose, mouth, and throat of individuals in the infective stage. This period begins 2 to 4 days before the appearance of the rash and lasts from 2 to 5 days thereafter. The first symptoms of measles, after an incubation period of 7 to 14 days, are fever, nasal discharge, and redness of the eyes. Characteristic white spots appear in the mouth, followed by a rash on the face that spreads to the rest of the body. The symptoms disappear in 4 to 7 days. One attack of measles confers lifelong immunity. However, it renders the patient susceptible to other more serious infections such as bronchial pneumonia and encephalitis. The measles virus has also been associated with subacute sclerosing panencephalitis (SSPE), which causes chronic brain disease in children and adolescents. After the attack of measles, it can cause intellectual deterioration, convulsive seizures, and motor abnormalities and is usually fatal. Common measles in pregnant women can be a threat to the unborn child, and vaccination of women well before pregnancy is recommended (see also rubella, or German measles).

Immunization by injection of live measles-virus vaccine, first marketed in 1963, has proven effective. Given at first with gamma globulin, the vaccine was further developed by 1965 so that one shot alone gives long-term, probably lifetime, immunity; a nationwide program was established in the United States for the vaccination of all children over the age of nine months.

German measles: see rubella.

or rubeola

Highly contagious viral childhood disease. It initially resembles a severe cold with red eyes and fever; a blotchy rash and higher fever later develop. After recovery, patients have lifelong immunity. Adult patients tend to have more severe cases. Antibiotics now prevent death from secondary infections. Measles itself, for which there is no drug, requires only bed rest, eye protection, and steam for bronchial irritation. A vaccine developed in the 1960s proved not to give permanent immunity and is too heat-sensitive for use in tropical areas. The worldwide incidence of measles continues to rise. Research is currently directed toward development of a more stable vaccine. Seealso rubella.

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or German measles

Viral disease with a usually mild course, except in women in the first 20 weeks of pregnancy, in whom it can cause fetal birth defects (of eyes, heart, brain, and large arteries) or death. Sore throat and fever are followed by swollen glands and a rash. Up to 30percnt of infections may have no symptoms. Lifelong immunity follows infection. Encephalitis is a rare complication. Rubella was not distinguished from measles (rubeola) until the early 19th century and was not known to be dangerous until 1941. The virus was isolated in 1962, and a vaccine became available in 1969.

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