[4] The name is derived from Latin parvum, meaning small, reflecting the fact that B19 ranks among the smallest DNA viruses.

It is the classic cause of the childhood rash called fifth disease or erythema infectiosum, or "slapped face syndrome".

[9] Human parvovirus B19 is a non-enveloped, icosahedral virus that contains a single-stranded linear DNA genome of approximately 5,600 base pairs in length.

This diversifying selection is consistent with persistent infection as this part of the VP1 protein contains epitopes recognised by the immune system.

[citation needed] Like other nonenveloped DNA viruses, pathogenicity of parvovirus B19 involves binding to host cell receptors, internalization, translocation of the genome to the host nucleus, DNA replication, RNA transcription, assembly of capsids and packaging of the genome, and finally cell lysis with release of the mature virions.

[22] In humans the P antigen (also known as globoside) is the cellular receptor for parvovirus B19 virus that causes erythema infectiosum (fifth disease) in children.

[citation needed] Studies of Parvovirus B19 (B19V) have provided insights into its persistence and integration within human tissues.

Although B19V DNA integration has been observed in vitro, its low prevalence in sampled tissues suggests that alternative mechanisms may contribute to lifelong persistence.

In one case involving pulmonary carcinoma, a B19V integration junction was found in the colon, indicating possible interactions with host genomic elements.

[citation needed] The virus is primarily spread by infected respiratory droplets; however, blood-borne transmission has also been reported.

The B19V infection starts with flu-like symptoms consisting fever, headache, runny nose, sore throat, joint pain and rash.

[30] Individuals with B19 IgG antibodies are generally considered immune to recurrent infection, but reinfection is possible in a minority of cases.

It is so named because it was the fifth most common cause of a pink-red infection associated rash to be described by physicians (many of the others, such as measles and rubella, are rare now).

[33] The following symptoms are characteristic: Teenagers or young adults may develop the so-called Papular purpuric gloves and socks syndrome.

[37]: 401 In 1996, an association with parvovirus B19 was described, after virus was demonstrated in skin biopsy samples,[38] subsequently corroborated in numerous publications.

[39] [40] Arthralgias and arthritis are commonly reported in association with parvovirus B19 infection in adults in the absence of skin findings, whereas erythema infectiosum is the main symptom observed in children.

The occurrence of arthralgia coincides with the initial detection of circulating IgM- and IgG-antibodies against the viral structural proteins VP1 and VP2.

Possibly up to 15% of all new cases of arthritis are due to parvovirus, and a history of recent contact with a patient and positive serology generally confirms the diagnosis.

Parvovirus B19 is a cause of chronic anemia in individuals with immunodeficiency, receiving immunosuppressive therapy or with HIV infection.

[45] Parvovirus infection in pregnant women is associated with hydrops fetalis due to severe fetal anemia, sometimes leading to miscarriage or stillbirth.

The risk to the fetus will be reduced with correct diagnosis of the anemia (by ultrasound scans) and treatment (by blood transfusions).

The reaction was either to the PLA2 activity releasing arachidonic acid and precursors of inflammatory mediators or the usage of insect cells.