() in Jiangsu Province, China. We collected 83 crayfish during the period between July 2008 and June 2010. Of these, 42 were tested positive for WSSV using the loop-mediated isothermal amplification method (LAMP). Based on geographical and time considerations, we selected six positive samples for amplification of the variable and deletion regions of the WSSV genome. In addition, we used PCR amplification to clone and sequence these regions. We then conducted a pairwise and multiple alignment analysis to evaluate the degree of genetic divergence between different strains. The variable region was ~1 440 bp in length in most strains, except in isolate WSSV-XH(1 829 bp). The deletion region was 384 bp in length in six strains, and there was complete homology among the nucleotide sequences. We compared the isolate sequences to those in GenBank and found at least two distinct types of WSSV in Jiangsu Province. Given this, we hypothesize that the WSSV variable region and the deletion region may have evolved independently.