Parvovirus B19 infects red blood cell (RBC) precursor cells (and other tissues expressing the 'p antigen' receptor). Using the host cells mechanisms, the virus replicates and causes cell lysis resulting in the shut-down of RBC production.
Consequences of this in the well people are not clinically apparent since the time taken to mount an antibody response followed by a return to normal RBC production is less than the life span of existing RBCs.
In childhood, the age for most primary infections, illness is described as 'slapped cheek' disease, 5
th
disease or
erythema infectiosum.
Symptoms may include sore throat and fever corresponding to the peak of viraemia, and infection transmission via respiratory aerosol. (approx. 7 to 10 days post exposure ), followed several days later by a distinctive facial rash associated with the antibody response. In adulthood, arthralgia/arthritis is a prominent symptom.
In-patients with haemolytic disorders infection can result in critical aplastic anaemias. Immunocompromised patients may also develop chronic parvovirus infection. RBC transfusions and immunoglobulin therapy can be successful for such cases.
Rare but serious consequences can result from infection during pregnancy.
Hydrops fetalis
, miscarriage and still birth have been associated with infection at different stages of gestation.
Due to (a) the transient nature of parvovirus B19 viraemia, (b) the appearance of prominent clinical symptoms after the peak of viraemia and (c) the unreliable serology of immunocompromised patients, the use of PCR for sensitive detection of parvovirus B19 DNA is helpful for the diagnosis of parvovirus B19 infection.
References
1. Primer sequences are taken from the published Parvovirus B19 sequence in J.Virol. 1986 58(3) 921-936. Shade,R.
et al.
2. Tolfvenstam, T. et al. Frequency of human parvovirus B19 infection in intrauterine fetal death Lancet 2001;357:1-1494-7
Parvovirus serology
