In 1997, white spot syndrome virus (WSSV) was discovered in shrimp culture facilities in South Carolina, USA. This disease was known to cause devastating mortalities in cultured populations in Southeast Asia and prompted concern for the health of wild populations in the USA. Our study surveyed wild shrimp populations for the presence of WSSV by utilizing molecular diagnostics and bioassay techniques. A total of 1150 individuals (586 Litopenaeus setiferus, 477 Farfantepenaeus aztecus and 87 F. dourarum) were examined for the presence of WSSV DNA by PCR. A total of 32 individuals tested positive and were used in a bioassay to examine the transmission of disease to healthy individuals of the culture species L. vannamei. DNA sequencing of PCR products from a positive individual confirmed that the positive individuals carried WSSV DNA. Significant mortalities were seen in test shrimp injected with tissue extracts from heavily infected wild shrimp. These data confirm the existence of WSSV in wild shrimp stocks along the Atlantic Coast and that the virus can cause mortalities in cultured stocks.KEY WORDS: Penaeid · Shrimp · White spot virus · Disease · Native species · PCR Resale or republication not permitted without written consent of the publisherDis Aquat Org 59: [179][180][181][182][183][184][185] 2004 shipped to South Carolina from a previously certified SPF (specific pathogen free) producer that had become contaminated. Since 1996, South Carolina has not had any further TSV epizootic events. In January of 1997, WSSV was identified at culture facilities in South Carolina.WSSV was first reported from Northeast Asia in 1992 and spread throughout the region during the 1990s causing devastating declines in farmed shrimp production (Flegel 1997). WSSV was identified in captive shrimp in South Carolina in 1997, and the available evidence suggested the infections were derived from the wild (Browdy & Holland 1998). WSSV is unique among shrimp viruses in that it infects a variety of crustaceans. WSSV-like genetic material has been found in samples from white shrimp, grass shrimp, fiddler crabs, blue crabs, and stone crabs in South Carolina (R.W.C. unpubl. data). These crustaceans potentially serve as reservoirs for WSSV, with the possibility of re-infecting wild as well as farmed shrimp populations. Archived DNA samples suggest a WSSVlike virus may have existed in the southeastern USA as early as 1988 (R.W.C. unpubl. data). At present, there are not sufficient data to determine whether the WSSV infections identified in captive white shrimp in South Carolina resulted from a recent introduction from Asia or from indigenous carriers.Risks of shrimp virus introduction are not limited to transfer of live animals for shrimp culture. Two other potentially important sources of shrimp viruses are carrier organisms in ship ballast water and frozen seafood products. Invasions of a wide range of nuisance organisms, including a number of crustaceans, have been linked to the release of ballast water (Carlton 1992). In many...