DAO 63:101-106 (2005)  -  doi:10.3354/dao063101

Taura syndrome virus (TSV) in Thailand and its relationship to TSV in China and the Americas

Linda Nielsen1, Wiwat Sang-oum1, Supapon Cheevadhanarak2, Timothy W. Flegel1,*

1Centex Shrimp, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand and National Centerfor Genetic Engineering and Biotechnology, 113 Paholyothin Rd., Klong 1, Klong Luang, Phtthumthani 12120, Thailand
2School of Bioresources and Technology, King Mongkut’s University of Technology, Thonburi, Bangkuntien,Bangkok 10150, Thailand
*Corresponding author. Email:

ABSTRACT: The cultivation of exotic Penaeus vannamei in Thailand began on a very limited scale in the late 1990s, but a Thai government ban on the cultivation of P. monodon in freshwater areas in 2000 led many Thai shrimp farmers to shift to cultivation of P. vannamei. Alarmed by the possibility of Taura syndrome virus (TSV) introduction, the Thai Department of Fisheries required that imported stocks of P. vannamei be certified free of TSV by RT-PCR (Reverse Trasciption Polymerase Chain Reaction) testing. During the interval of allowed importation, over 150000 broodstock shrimp were imported, 67% of these from China and Taiwan. Despite the safeguards, TSV outbreaks occurred and we confirmed the first outbreak by RT-PCR in early 2003. This resulted in a governmental ban on all shrimp broodstock imports from February 2003, but TSV outbreaks have continued, possibly due to original introductions or to the continued illegal importation of stocks. To determine the origin of the TSV in Thailand, the viral coat protein gene VP1 was amplified by RT-PCR from several shrimp specimens found positive for TSV by RT-PCR from January to November 2003. These included 7 samples from P. vannamei disease outbreaks in Thailand, 3 other non-diseased shrimp samples from Thailand and Burma and 6 samples including P. vannamei and P. japonicus from China. Comparison revealed that the Thai, Burmese and Chinese TSV types formed a clade distinct from a clade of TSV types from the Americas.


KEY WORDS: Taura syndrome virus · TSV · Thailand · Phylogeny · VP1


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