Fifth disease is a mild illness, usually without a significant fever, caused by parvovirus B19. Severe complications are rare but people with chronic blood disorders may develop an inability to form new blood cells and develop anemia. During pregnancy the virus can infect the unborn child, which can result in damage to, or death of the fetus.
How is it transmitted?
It is spread by exposure to secretions or droplets from the nose and throat. It occurs more commonly in children of elementary school age. A person is most contagious about one week before the onset of the rash, and once the rash starts, it probably cannot be spread to others.
The symptoms may start with a low grade fever and fatigue. A red rash which looks like a slap mark commonly appears on the cheeks and a fine lace-like rash may appear on the body. The rash may be itchy. Some people have mild signs of illness or no symptoms at all. The above symptoms are more common in children. Adults more commonly have arthritic pain and less rash or fever.
Symptoms start 1-2 weeks after exposure.
There is no specific treatment, however if you have had fifth disease it is thought that you develop long-term immunity. Studies show that about 50% of adults have immunity to fifth disease.
You do not have to be excluded from work or school because the contagious stage happens before most of the symptoms. Pregnant women should try to avoid exposure to infected children and especially family members or playmates of recently diagnosed persons. Pregnant women with sick children at home should be advised to wash hands frequently and avoid sharing eating utensils.
The virus doesn't cause birth defects but 10% of babies who are infected with fifth disease before birth develop severe anemia and 1-2% may even die. A pregnant woman should come in for a blood antibody test drawn as soon as they are exposed to a child with fifth disease. This test will tell if you have already had the disease and are protected from becoming infected again. If you are not immune, during the first trimester there is a slight 1-2% increase in risk of miscarriage. If you are in the 2nd or 3rd trimester the virus could break down some of the baby's red blood cells causing anemia but is unlikely to be severe enough to harm the baby. Monthly ultrasounds are used to follow the baby for signs of hydrops (sign of severe anemia).
EVEN IF YOU ARE NOT IMMUNE, YOU MAY NOT HAVE BEEN INFECTED WITH THE VIRUS DESPITE CLOSE EXPOSURE TO A CHILD WITH FIFTH DISEASE.
A second blood test in a few weeks will show if you have been recently infected with the virus, which then would require the monthly ultrasounds mentioned above. If you do get fifth disease you still only have a very slight risk of the baby being harmed.