Description
Rubella is an acute exanthematous viral infection of children and adults. Rash, fever and lymphadenopathy characterize the illness.This contagious viral infection can be prevented by vaccine and is known by its distinctive red rash.The disease can spread through direct contact with the saliva or mucus of an infected person or through the air by respiratory droplets produced from coughing or sneezing.
During pregnancy this virus can cause congenital rubella syndrome leading to fetal demise, malformation, deafness and mental retardation.A rubella test is usually done for a woman who is or wants to become pregnant to determine whether she is at risk for rubella. Several laboratory methods can be used to detect rubella antibodies in the blood. The most commonly used method is the enzyme-linked immunosorbent assay (ELISA, EIA).
There is no cure for rubella, only supportive treat- ment, such as bed rest, fluids, and fever reduction. Rubella isn`t the same as measles, but the two illnesses share some symptoms, including the red rash. Rubella is caused by a different virus than measles, and rubella isn`t as infectious or as severe as measles.Hence the best way is immunization and the measles-mumps-rubella (MMR) vaccine is highly effective in preventing rubella.
A rubella test detects and measures rubella antibodies in the blood that are produced by the body`s immune system in response to immunization or an infection by the rubella virus.
There are two types of rubella antibodies that lab tests can detect, IgM and IgG: The first type to appear in the blood after exposure is the IgM rubella antibody. The level of this protein rises and peaks in the blood within about 7 to 10 days after infection and then tapers off over the next few weeks, except in an infected newborn, in whom it may be detected for several months to a year.
The IgG rubella antibody takes a bit longer to appear than the IgM, but once it does, it stays in the bloodstream for life, providing protection against re-infection. The presence of IgM rubella antibodies in the blood indicates a recent infection while the presence of IgG antibodies may indicate a recent or past rubella infection, or indicate that a rubella vaccine (a measles, mumps, rubella vaccine) has been given and is providing adequate protection.Since rubella antibodies take some time to appear after infection, the tests may be repeated after day 5 of illness onset (IgM) and 7-21 days after the first specimen (IgG) to see if the antibody levels have become detectable (when initially absent) and to determine whether the levels are rising or falling over time.
