A new genome type of human parvovirus B19 present in sera of patients with encephalopathy.

The possible involvement of human parvovirus B19 infection in encephalopathy has been reported. To determine the characteristics of B19 viruses involved in such cases, we molecularly cloned a part of the B19 DNAs derived from the sera of three patients with encephalopathy (B19 strains N80, N81 and N82), following amplification by PCR. The nucleotide (nt) sequences of the cloned DNAs (nt 3147-3405) were then determined. The nucleotide sequence of N80 was similar to that of the known genome type of group II. The nucleotide sequences of N81 and N82 were similar to each other, but distinctly different from those of other B19 strains reported previously. Almost the entire genome of strain N81 (nt 229-4812) was molecularly cloned following amplification by PCR. Analyses of the restriction site polymorphisms of the cloned N81 DNAs showed that N81 is distantly related to other B19 strains. Therefore, the two strains of N81 and N82 were defined as belonging to a new genome type, group V. Group V B19 virus has so far been isolated only from patients with encephalopathy.