A densovirus newly isolated from the smoky-brown cockroach Periplaneta fuliginosa

We purified a causing agent of fetal disease for smoky-brown cockroach Periplaneta fuliginosa, which was designated as "cockroach small spherical virus (CSSV)". Purified virus particles had a diameter of 22 +/- 0.6 nm and contained DNA as a single-stranded form. However, the extraction of DNA under condition of appropriate high salt and elevated temperature yielded a double-stranded DNA with a size of 5,500 nucleotides. These results were quite similar to those of other densoviruses (DNVs). The CSSV had five structural proteins (VP1: 52 KDa, VP2: 56 KDa, VP3: 79 KDa, VP4: 82 KDa, and VP5: 105 KDa). The SDS-PAGE profile of these proteins was quite different from that of the cockroach DNV previously reported and was rather similar to that of Bombyx mori (Bm) DNV-1. An immunochemical study, however, demonstrated that there was no immunological relationship between the CSSV and the Bm DNV-1. These data suggest that the CSSV is a new member of DNV.