Novel human erythrovirus associated with transient aplastic anemia.

Erythrovirus (formerly parvovirus) B19 causes a wide range of diseases in humans, including anemia due to aplastic crisis. Diagnosis of B19 infection relies on serology and the detection of viral DNA by PCR. These techniques are usually thought to detect all erythrovirus field isolates, since the B19 genome is known to undergo few genetic variations. We have detected an erythrovirus (V9) markedly different from B19 in the serum and bone marrow of a child with transient aplastic anemia. The B19 PCR assay yielded a product that hybridized only very weakly to the B19-specific probe and whose sequence diverged more from those of 24 B19 viruses (11 to 14%) than the divergence found within the B19 group (</=6.65%). Restriction enzyme analysis of the V9 genome revealed that this genetic divergence extended beyond the amplified region. Interestingly, serological tests failed to demonstrate a response characteristic of acute B19 infection. V9 could be a new erythrovirus, and new diagnostic tests are needed for its detection.