New genotypes of white spot syndrome virus (WSSV) and Taura syndrome virus (TSV) from the Kingdom of Saudi Arabia.

White spot syndrome virus (WSSV) and Taura syndrome virus (TSV) are highly pathogenic to penaeid shrimp and have caused significant economic losses in the shrimp culture industry around the world. During 2010 and 2011, both WSSV and TSV were found in Saudi Arabia, where they caused severe mortalities in cultured Indian white shrimp Penaeus indicus. Most outbreaks of shrimp viruses in production facilities can be traced to the importation of infected stocks or commodity shrimp. In an attempt to determine the origins of these viral outbreaks in Saudi Arabia, we performed variable number of tandem repeat (VNTR) analyses for WSSV isolates and a phylogenetic analysis for TSV isolates. From the WSSV genome, the VNTR in open reading frames (ORFs) 125 and 94 were investigated with PCR followed by DNA sequence analysis. The genotypes were categorized as {N125, N94} where N is the number of repeat units in a specific ORF, and the subscript indicates the ORF (i.e. ORFs 125 and 94 in this case). From 15 Saudi Arabia WSSV isolates, we detected 3 genotypes: {6125, 794}, {7125, del94}, and {8125, 1394}. The WSSV genotype of {7125, del94} appears to be a new variant with a 1522 bp deletion encompassing complete coding regions of ORF 94 and ORF 95 and the first 82 bp of ORF 93. For TSV genotyping, we used a phylogenetic analysis based on the amino acid sequence of TSV capsid protein 2 (CP2). We analyzed 8 Saudi Arabian isolates in addition to 36 isolates from other areas: SE Asia, Mexico, Venezuela and Belize. The Saudi Arabian TSV clustered into a new, distinct group. Based on these genotyping analyses, new WSSV and TSV genotypes were found in Saudi Arabia. The data suggest that they have come from wild shrimp Penaeus indicus from the Red Sea that are used for broodstock.