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Rubella - the disease
What is rubella?
Rubella is an infection caused by a virus. Congenital rubella syndrome (CRS) is an important cause of severe birth defects. When a woman is infected with the rubella virus early in pregnancy, she has a 90% chance of passing the virus on to her fetus. This can cause the death of the fetus, or it may cause CRS. Even though it is a mild childhood illness CRS causes many birth defects. Deafness is the most common, but CRS can also cause defects in the eyes, heart, and brain. It is estimated that there are 700 000 deaths due to CRS each year.
How is rubella spread?
Rubella is spread in airborne droplets when infected people sneeze or cough. Once a person is infected, the virus spreads throughout the body in about five to seven days. During this time, pregnant women may pass the virus on to their fetuses.
Infected people are most likely to pass on the virus when the rash is developing. But the virus may be spread from seven days before to about seven days after the rash appears.
Infants with CRS can transmit the virus for a year or more.
What are the signs and symptoms of rubella?
The time between first contact with the virus and the first sign of rubella is about 14 days. Symptoms are often mild, and between 20% and 50% of infected people may notice no symptoms at all.
In children, a rash is usually the first sign; other signs include low fever and swollen lymph nodes in the neck. The rash most often begins on the face and spreads from head to foot. It usually lasts for about three days. The rash is pink, and fainter than measles. Many rashes mimic rubella, and a rash should not be considered a sure sign of infection with the rubella virus.
Infants who are born with CRS usually show symptoms such as cataracts and loss of hearing in infancy, but they may not show symptoms for two to four years.
What are the complications of rubella?
Complications tend to occur more often in adults than in children. About 70% of adult women who are infected may develop pain in their joints or arthritis, especially in the fingers, wrists, and knees. Encephalitis occurs in about one in 5000 cases and is most common in adult women. Problems with bleeding occur in about one in 3000 cases, usually among children.
Complications from CRS include deafness, cataracts, heart defects, and mental retardation.
What is the treatment for rubella?
There is no specific treatment for rubella or for CRS. Patients with rubella should drink plenty of fluids and may take medication to reduce mild fever. Infants with CRS are treated for their specific problems.
How is rubella prevented?
Rubella vaccines are safe and effective and for infant immunization are usually given in combination with measles/mumps vaccine as MMR. In some countries, mostly in the industrialized world, rubella has been nearly eliminated through childhood immunization programmes. However, it is important to ensure that coverage in infants is sustained at over 80% to avoid shifting of rubella transmission to older age groups. For prevention of CRS, women of childbearing age are the primary target group for rubella immunization. Immunizing women between the ages of 15 and 40 will rapidly reduce the incidence of CRS without affecting childhood transmission of the rubella virus.
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