PURIFICATION AND GENOMIC ANALYSIS OF BACULOVIRUS ASSOCIATED WITH WHITE SPOT SYNDROME (WSBV) OF PENAEUS-MONODON

The causative viral agent was purified from diseased shrimp Penaeus mo nodon with white spot syndrome. Negatively stained preparations show t hat the virus is pleiomorphic. It is fusiform or rod-shaped. In negati vely stained preparations, the virion measures 70 to 150 nm at its bro adest point and is 250 to 380 nm long. In some virions, a tail-like pr ojection extends from one end. The capsid is apparently composed of ri ngs of subunits in a stacked series. The rings are aligned perpendicul ar to the longitudinal axis of the capsid. The genome of the virus is a double-stranded DNA molecule which produces at least 22 Hind III fra gments. The full length of the DNA is estimated to be longer than 150 kbp. Based on the morphological characteristics and genomic structures of the virus, we confirm that white spot syndrome associated virus (W SSV) is a member of genus NOB (Non-Occluded Baculovirus) of the subfam ily Nudibaculovirinae of Baculoviridae, name the present isolate PmNOB III, and propose the use of WSBV (Baculovirus associated with White Sp ot syndrome) to indicate PmNOBIII related agents.