Parvovirus B19 clearance from peripheral blood after acute infection.

The clearance of B19 parvovirus from peripheral blood was followed after acute infection to determine how long the virus is present in blood, even at low titer. The presence of B19 DNA in serum was investigated with dot blot hybridization during an epidemic. Fourteen patients positive for B19 DNA were followed for up to 1 year for its presence in samples taken monthly, using both dot blot hybridization and nested polymerase chain reaction (PCR). All patients examined showed medium to high viremic titers (detectable with hybridization assay) only at the beginning of observation; later the virus titer decreased and was detectable only by nested PCR. Of the 14 patients followed, 13 were positive for B19 DNA by nested PCR for 2-6 months; 1 patient showed a persistent infection associated with chronic arthritis and was positive for B19 DNA for 1 year without clearance of the virus.