Roughly 50-75% of all pregnant women are immune to parvovirus B19 while the remainder of women are susceptible to mild illness. A majority of fetuses who do contract parvovirus B19 show either no significant symptoms or complete resolution of the virus. However, the following serious complications are rare but possible: miscarriage, stillbirth, fetal anemia, hepatic failure, and abnormal neurodevelopment outcome. In some cases, fetuses would develop hydrops fetalis due to congenital parvovirus B19. This condition was studied as a determinant of later fetal outcomes, such as miscarriage or perinatal death, in 2016 systematic review. The review showed that those born with parvovirus B19 that caused hydrops fetalis did have an association with higher mortality risk and higher risk of complications. While the potential consequences of erythema infectiosum can be quite serious in pregnancy, mothers can be tested for immunity via the presence of IgG and IgM antibodies.In addition to fetuses, parvovirus B19 infection and its effects has been studied in adults as well. The virus has also been associated with the development of neurological complications, as identified in a systematic review in 2014. This analysis included a total of 89 studies covering complications in both the central and nervous system such as encephalitis, meningitis, and peripheral neuropathy. However, the specific pathophysiology of these complications has yet to be discovered but the review does encourage the use of antibody testing to determine a patients risk. Infection of this virus is not limited to the nervous system.
It manifests in painful swelling of the joints that feels similar to arthritis. Older children and adults with fifth disease may have difficulty in walking and in bending joints such as wrists, knees, ankles, fingers, and shoulders.The disease is usually mild, but in certain risk groups and rare circumstances, it can have serious consequences:

In pregnant women, infection in the first trimester has been linked to hydrops fetalis, causing spontaneous miscarriage. In people with sickle-cell disease or other forms of chronic hemolytic anemia such as hereditary spherocytosis, infection can precipitate an aplastic crisis. Those who are immunocompromised (HIV/AIDS, chemotherapy) may be at risk for complications if exposed. In less than 5% of women with parvovirus B19 infection, a baby may develop severe anemia leading to miscarriage. This occurs most often during the first half of pregnancy. Causes
Fifth disease, also known as erythema infectiosum, is caused by parvovirus B19, which only infects humans. Infection by parvovirus B19 can lead to multiple clinical manifestations, but the most common is fifth disease.Parvovirus B19 (B19V) is a small, single-stranded, non-enveloped DNA virus. Binding of B19V capsid to the cellular receptor globoside (Gb4Cer) results in a cascade of structural changes and subsequent signal transduction processes facilitating the entry of parvovirus B19 into the host cell. After gaining access to the host cell, BV19 binds to glycosphingolipid globoside (blood group P antigen) targeting erythroid lineage in the bone marrow.