[New human papovaviruses: JC and BK].

BK and JC viruses are human papovaviruses widespread in human population. Primary infection with those viruses are generally asymptomatic and reactivation occur upon immunodepression. JC virus found to be associated with Progressive Multifocal Leukoencephalopathy. In the other hand BK virus mostly reactivated after immunosuppression. Both viruses have oncogenic potential when inoculated subcutaneously or intracerebrally to experimental animals. However, there is no direct relation has been shown yet for association of those new human papovaviruses with human malignancies.