Detection of head-to-tail DNA sequences of human bocavirus in clinical samples.

Parvoviruses are single stranded DNA viruses that replicate in a so called "rolling-hairpin" mechanism, a variant of the rolling circle replication known for bacteriophages like φX174. The replication intermediates of parvoviruses thus are concatemers of head-to-head or tail-to-tail structure. Surprisingly, in case of the novel human bocavirus, neither head-to-head nor tail-to-tail DNA sequences were detected in clinical isolates; in contrast head-to-tail DNA sequences were identified by PCR and sequencing. Thereby, the head-to-tail sequences were linked by a novel sequence of 54 bp of which 20 bp also occur as conserved structures of the palindromic ends of parvovirus MVC which in turn is a close relative to human bocavirus.