Follow-up of 6 cases of persistent B19 infection. B19 DNA in case 1 (seroconversion to B19), in cases 2 and 3 (detection of B19 IgM), and in cases 4 to 6 (unknown date of B19 infection) was quantified by QPCR. Serial samples were available over 28 to 60 months. Quantitative results are shown in the graphs; qualitative VP1 and NS1 PCR results of the corresponding samples are shown on top of each graph as + for positive and - for negative. ND indicates not done. Detailed results of all B19 markers for case 1 are shown in Table 2.