Rubella

Alternative names:

German measles; three day measles

Definition:

A contagious viral infection with mild symptoms associated with a rash.

Causes, incidence, and risk factors:

The disease is caused by a virus that is spread through the air or by close contact. It can also be transmitted to a fetus by a mother with an active infection. The disease is usually mild and may even go unnoticed. Children may have few symptoms, but adults may experience a prodrome (warning symptom) of a fever, headache, malaise, runny nose, and inflamed eyes that lasts from 1 to 5 days before the rash appears. A person can transmit the disease from 1 week before the onset of the rash until 1 week after the rash disappears. The disease is not as contagious as rubeola (measles), therefore many people are not infected during childhood. Lifelong immunity to the disease follows infection. Epidemics may occur at about 6- to 9-year intervals. The risk factors are the unimmunized individuals. Only 1,400 cases were reported in the U.S. in 1991.

The disease is potentially serious because of the ability to produce defects in a developing fetus if the mother is infected during early pregnancy. As many as 10 to 15% of women in their childbearing years are susceptible to infection. Congenital rubella syndrome occurs in 25% or more of infants born to women who acquired rubella during the first trimester of pregnancy. Defects are rare if the infection occurs after the 20th week of pregnancy. One or more defects may occur in an infected fetus and include deafness, cataracts, microcephaly, mental retardation, congenital heart defects, and other defects. A miscarriage or stillbirth may occur.