Taura syndrome virus (TSV) in Thailand and its relationship to TSV in China and the Americas
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Date
2005Author
Nielsen, Linda
Sang-oum, Wiwat
Cheevadhanarak, Supapon
Flegel, Timothy W
Type
ArticleLanguage
enMetadata
Show full item recordAbstract
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 150 000 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.