As there are cross-reactivities between HBoV species in ELISA assay, we developed a cELISA assay to evaluate the seroprevalence of each HBoV species. We evaluated the specificity of this protocol using heterologous competition assays with parvovirus B19 and human parvovirus 4 (PARV4) VP2. Neither human parvovirus B19 nor PARV4 VP2 inhibited the reactivity of IgG against HBoV1, 2, 3, or 4 in the serum from adults or children ( Figure 3 ). These results suggest that there is no antigenic crossreactivity between HBoVs VP2 and human parvovirus B19 VP2 or between HBoVs VP2 and PARV4 VP2. To confirm the specificity of this ELISA protocol, we tested sera from 15 adults that were positive for human parvovirus B19. In the HBoV VLP ELISA, we did not detect false-positive signals for HBoVs (data not shown).