trunghieu1985
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Historic emergence, impact and current status of shrimp pathogens in Asia
Timothy W. Flegel
a b s t r a c t
It is estimated that approximately 60% of disease losses in shrimp aquaculture have been caused by viral
pathogens and 20% by bacterial pathogens. By comparison, losses to fungi and parasites have been
relatively small. For bacterial pathogens, Vibrio species are the most important while for viral pathogens
importance has changed since 2003 when domesticated and genetically selected stocks of the American
whiteleg shrimp Penaeus (Litopenaeus) vannamei (Boone 1931) replaced the formerly dominant giant tiger
or black tiger shrimp Penaeus (Penaeus) monodon (Fabricius 1798) as the dominant cultivated species. For
both species, white spot syndrome virus (WSSV) and yellow head virus (YHV) are the most lethal. Next
most important for P. vannamei is infectious myonecrosis virus (IMNV), originally reported from Brazil,
but since 2006 from Indonesia where it was probably introduced by careless importation of shrimp aquaculture
stocks. So far, IMNV has not been reported from other countries in Asia. Former impacts of Taura
syndrome virus (TSV) and infectious hypodermal and hematopoietic necrosis virus (IHHNV) on this species
have dramatically declined due to the introduction of tolerant stocks and to implementation of good biosecurity
practices. Another problem recently reported for P. vannamei in Asia is abdominal segment deformity
disease (ASDD), possibly caused by a previously unknown retrovirus-like agent. Next most important
after WSSV and YHV for P. monodon is monodon slow growth syndrome (MSGS) for which component
causes appear to be Laem Singh virus (LSNV) and a cryptic integrase containing element (ICE). Hepatopancreatic
parvovirus (HPV) and monodon baculovirus (MBV) may be problematic when captured P. monodon
are used to produce larvae, but only in the absence of proper preventative measures. Since 2009 increasing
losses with P. vannamei in China, Vietnam and now Thailand are associated with acute hepatopancreatic
necrosis syndrome (AHPNS) of presently unknown cause. Despite these problems, total production of cultivated
penaeid shrimp from Asia will probably continue to rise as transient disease problems are solved
and use of post larvae originating from domesticated SPF shrimp stocks in more biosecure settings expands.
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Timothy W. Flegel
a b s t r a c t
It is estimated that approximately 60% of disease losses in shrimp aquaculture have been caused by viral
pathogens and 20% by bacterial pathogens. By comparison, losses to fungi and parasites have been
relatively small. For bacterial pathogens, Vibrio species are the most important while for viral pathogens
importance has changed since 2003 when domesticated and genetically selected stocks of the American
whiteleg shrimp Penaeus (Litopenaeus) vannamei (Boone 1931) replaced the formerly dominant giant tiger
or black tiger shrimp Penaeus (Penaeus) monodon (Fabricius 1798) as the dominant cultivated species. For
both species, white spot syndrome virus (WSSV) and yellow head virus (YHV) are the most lethal. Next
most important for P. vannamei is infectious myonecrosis virus (IMNV), originally reported from Brazil,
but since 2006 from Indonesia where it was probably introduced by careless importation of shrimp aquaculture
stocks. So far, IMNV has not been reported from other countries in Asia. Former impacts of Taura
syndrome virus (TSV) and infectious hypodermal and hematopoietic necrosis virus (IHHNV) on this species
have dramatically declined due to the introduction of tolerant stocks and to implementation of good biosecurity
practices. Another problem recently reported for P. vannamei in Asia is abdominal segment deformity
disease (ASDD), possibly caused by a previously unknown retrovirus-like agent. Next most important
after WSSV and YHV for P. monodon is monodon slow growth syndrome (MSGS) for which component
causes appear to be Laem Singh virus (LSNV) and a cryptic integrase containing element (ICE). Hepatopancreatic
parvovirus (HPV) and monodon baculovirus (MBV) may be problematic when captured P. monodon
are used to produce larvae, but only in the absence of proper preventative measures. Since 2009 increasing
losses with P. vannamei in China, Vietnam and now Thailand are associated with acute hepatopancreatic
necrosis syndrome (AHPNS) of presently unknown cause. Despite these problems, total production of cultivated
penaeid shrimp from Asia will probably continue to rise as transient disease problems are solved
and use of post larvae originating from domesticated SPF shrimp stocks in more biosecure settings expands.
DOWNLOAD:
or
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