Parvovirus B-19 is a virus that commonly infects humans; about 50% of all adults have been infected sometime during childhood or adolescence. Parvovirus B-19 infects only humans. There are also animal parvoviruses, but they do not infect humans. Therefore, a person cannot catch parvovirus B-19 from a dog or cat.
The most common illness caused by parvovirus B-19 infection is "fifth disease," a mild rash illness that occurs most often in children. The ill child typically has a "slapped-cheek" rash on the face and a lacy red rash on the trunk and limbs. Occasionally, the rash may itch. The child is usually not very ill and the rash resolves in seven to ten days. Once a child recovers, he or she develops lasting immunity, which means
that the child is protected against future infection.
An adult who has not previously been infected with parvovirus B-19 can be infected and become ill, and develop a rash, along with joint pain or swelling, or both.
Fifth disease is usually a mild illness. It resolves without medical treatment among children and adults who are otherwise healthy. Joint pain and swelling in adults usually resolves in a week or so without long-term disability. During outbreaks of fifth disease, about 20% of adults and children are infected without getting any symptoms at all.
Usually, there are no serious complications for a pregnant woman or her baby because of exposure to a person with fifth disease. About 50% of women are already immune to parvovirus B-19; these women and their babies are protected from infection and illness. Even if a woman is susceptible and gets infected with parvovirus B-19, she usually experiences only a mild illness. Likewise, her unborn baby usually does not have any problems due to parvovirus B-19 infection.
Sometimes, however, parvovirus B-19 infection will cause the unborn baby to have severe anemia and the woman may have a miscarriage. This occurs in less than 5% of all pregnancies where the woman is infected and occurs more commonly during the first half of pregnancy. There is no evidence that parvovirus B-19 infection causes birth defects or mental retardation.
If you have been in contact with someone who has fifth disease or if you have an illness that might be caused by parvovirus B-19, you may want to talk to your healthcare provider. Your physician may perform a blood test to see if you are currently infected with parvovirus B-19 or whether you have evidence of a past infection and are immune.
A blood test for parvovirus B-19 may show 1) that you are immune to parvovirus B-19 and have no sign of recent infection; 2) that you are not immune and have not yet been infected; or 3) that you are currently or were recently infected. If you are immune, then you have nothing further to be concerned about. If you are not immune and not yet infected, then you may wish to avoid further exposure during
your pregnancy. If you have had a recent infection, you should discuss with your physician what you should do to monitor your pregnancy.
There is no universally recommended approach to monitoring a pregnant woman who has a documented parvovirus B-19 infection. Some physicians treat a parvovirus B-19 infection in a pregnant woman as a low-risk issue and they continue to provide routine prenatal care. Other physicians may increase
the frequency of visits and perform tests to monitor the unborn baby’s health. If the baby appears to be ill, there are special diagnostic and treatment options available. Your obstetrician will discuss these options with you.
There is no vaccine or medicine that prevents parvovirus B-19 infection. Frequent hand washing is recommended to reduce the spread of parvovirus B-19. Excluding persons with fifth disease from work, childcare centers, schools, etc. is not likely to prevent the spread of parvovirus B-19, since ill persons are contagious before they develop the characteristic rash.
The Center for Disease Control and Prevention does not recommend that pregnant women routinely be excluded from work where a fifth disease outbreak is occurring.
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