Additional to the PCR assays, HBoV can be detected indirectly via detection of antibodies to HBoV. This method has also been performed with different ELISAs using virus-like-particles (VLP) of HBoV VP1 or VP2 [30, 31, 32, 33] . VLPs were produced by using an insect cell line infected with a baculovirus expression vector. These VLPs were then used to produce rabbit anti-serum with high titers of immunoglobulins specific for HBoV, which could be used in the ELISA. All established ELISAs were able to detect anti-HBoV antibodies in sera.