Taura syndrome virus in Penaeus vannamei shrimp originating from Hawaii

Previously in Diseases of Aquatic Organisms (DAO) we reported the detection of Taura syndrome virus (TSV) from Penaeus vannamei cultured in Cheonsu Bay, South Korea (we named it KOR-CsPv04TSV) and imported from Hawaii (KOR-ImPv05TSV) (Do et al. 2006). Lightner et al. (2007, this issue) commented that our report on the detection of TSV from Hawaiian P. vannamei is ‘...not only incorrect, but also disturbing...’. According to their Comment, their opinion was based on the following. First, TSV has not been detected in Hawaii since 1994 (Lightner et al. 1995) and the absence of TSV has been confirmed by a routine testing and surveillance program administered by the Hawaii Aquaculture Development Program. Second, the Oceanic Institute has developed specific pathogen-free (SPF) shrimp stocks and the Hawaiian shrimp culture industry has produced and exported only SPF shrimp (Wyban et al. 1993, Pruder et al. 1995). Third, there were no complaints from any importing country regarding broodstock exports from Hawaii in 2004, 2005 or 2006. In addition, Lightner et al. (2007) stated that, even though the Hawaiian supplying company requested that we (i.e. the National Fisheries Research and Development Institute of Korea, NFRDI) carry out additional testing with additional samples from the same stock, we did not respond. They further stated that, in failing to notify the Competent Authority (in this case, the Hawaiian Aquaculture Development Program), we did not follow World Animal Health Organization (OIE) guidelines. They concluded that we incorrectly interpreted our test results, which were more likely the result of mislabeling of samples or within-laboratory contamination. In reply to their comments, we will first describe the situation when we detected TSV from Hawaiian broodstock of Penaeus vannamei. Korean shrimp farmers had previously cultured P. monodon and P. chinensis but production of these shrimp species rapidly declined due to the spread of white spot syndrome virus (WSSV) (Park et al. 1998, Moon et al. 2003, Seok et al. 2004). As an alternative, since 2002, Korean shrimp farmers have imported P. vannamei from various countries. P. vannamei is highly susceptible to Taura syndrome virus (TSV) (Brock et al. 1997, Overstreet et al. 1997); however, Korea was considered to be free of TSV and, in order to prevent the introduction of TSV, NFRDI screens every imported stock of shrimp for specific pathogens, especially TSV, by RT-PCR. From 2002 to 2004, Korea imported P. vannamei from Hawaii and China. In total, 19 consignments of pre-shipment samples were tested for specific pathogens; 10 consignments of broodstocks from Hawaii and 9 consignments of post-larvae from China. Among them, 6 consignments from China tested positive for infectious hypodermal and haematopoietic necrosis virus (IHHNV) and WSSV and were not approved for importation. The other 13 consignments tested negative for specific pathogens and were approved for importation. We did not detect TSV in any of the 19 samples. However, as we reported previously in DAO (Do et al. 2006), in 2004, mass mortality occurred among P. vannamei cultured in a shrimp farm on the western coast of Korea and we isolated TSV from the moribund shrimp (KOR-