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Whatever can go wrong, will go wrong.
Murphy’s Law
Transboundary Aquatic Animal
Diseases
 Caused by biological agents
 Highly contagious
 Often spread rapidly and cause high
morbidity/mortality in naïve populations
 May be new or emerging diseases
 Usually require drastic measures to eliminate from
aquaculture systems and are impossible or difficult to
eradicate once established in wild populations
Recent TAADs: Koi Herpes Virus (KHV)
Global Distribution of KHV
UK (1996, 1998, 2002, 2008), Germany (1997, 2001,
2002, 2003), Belgium (1999), Netherlands (2002),
Denmark (2002), Austria (2001), Slovenia (2008)
Japan (2003)
Taiwan (2002)
China (2002)
USA
Israel
(1998, 1999)
(1998)
Thailand (2004)
Malaysia (2000,
2001, 2007 ??)
Indonesia
(2002)
Koi Herpes Virus
 Classical example of a disease originating in an
ornamental fish (koi) that spread to cultured
foodfish (comon carp) and wild fisheries.
 Strong evidence of the importance of ornamental
fish as vectors for TAADs (+ SVC, ranaviruses,
parasites, bacteria
 In most countries, the ornamental fish trade is
poorly regulated.
 Assumptions (based on species & end use) that the
ornamental trade does not involve risk of disease
transfer are not supported by practical experience.
Recent TAADs: White Spot Syndrome
Virus (WSSV)
 WSSV is the most serious pathogen of
cultivated shrimp in the world
 Major pathways are through
movement of infected postlarvae and
broodstock
 Shrimp viral disease epidemics show
the distance & speed that aquatic
animal pathogens can be spread by
poor aquaculture practices
Recent TAADs: White Spot Syndrome
Virus (WSSV)
Shrimp viral disease epidemics
also show:
 The time lags between:
 disease appearance,
 its characterization,
 the development of reliable diagnostics
tests,
 its listing by the OIE & other
international actions.
The Asian Pandemic
1993
1993
1991/2
1993
1999
1993
1994
From Dr. P. Walker, CSIRO, Australia
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Emergence & Spread of WSSV in the Americas
1996
1997
1995
2000
2000
1999
1999
1999
Global Movements of Live Shrimp
Hawaii
Tahiti
From Prof. Donald Lightner, UOA
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Global Distribution of WSSV
North America
USA
Mexico
Latin America
Colombia
Ecuador
Guatemala
Honduras
Nicaragua
Panama
Peru
Brazil
Costa Rica
El Salvador
Middle East
Iran
South Asia
Bangladesh
India
Sri Lanka
Southeast Asia
Thailand
Malaysia
Indonesia
Myanmar
Philippines
Singapore
Viet Nam
East Asia
P.R. China
Japan
Taiwan POC
South Korea
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Recent TAADS: Epizootic Ulcerative Syndrome
 1971 - first described in Japan as an Aphanomyces
(fungal) infection by Egusa and Masuda (1971)
 mycotic granulomatosis (MG)
 1972 - epizootic cutaneous ulcerative syndrome in
estuarine fishes in Australia
 red spot disease (RSD)
 since 1978 - USA
 ulcerative menhaden disease (UM)
 1985 - major outbreaks since 1985 in Asia
 Epizootic ulcerative syndrome (EUS)
Ayu (Plecoglossus altivelis) infected with mycotic
granulomatosis in Japan
EUS affected farmed silver perch
(Bidyanus bidyanus) from Eastern Australia
Snakehead (Channa sp.) in the Philippines (1985)
showing typical EUS lesions
‘
Wild mullet (brackishwater) in the Philippines
infected with EUS
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1971
1989
1996
1989
1983
1991
1988
1984
1985
1981
1983
1987
Epizootic Ulcerative
Syndrome (EUS)
spread 1972-1996
1984
1979
1980
Australia, Bangladesh, Bhutan, Cambodia, India, Indonesia, Japan, Lao PDR,
Malaysia, Nepal, Philippines, Pakistan, Sri Lanka, Thailand, Vietnam
1972
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EUS in Africa: 2006
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Global Distribution of Epizootic Ulcerative Syndrome
USA since 1978
Africa: since 2006
Asia: since 1971
Some Estimates of Losses due to Finfish Diseases
1983
1989
Indonesia
Thailand
1990/92
1990
1994-98
2002
China
Malaysia
Japan
Indonesia
Japan
Norway
Canada
Annually
Annually
Lernaea cyprinacea US$ 11.4 M
Seabass diseases
US$ 0.8 M
Grouper diseases
US$ 1.07 M
Bacterial diseases
US$ 120 M
Vibriosis
US$ 7.4 M
Marine fish diseases US$ 114.4 M
KHV
US$ 15 M
KHV
US$ 1.4 M
ISA
US$ 11 M
ISA
US$ 14 M
KHV = koi herpes virus, ISA = infectious salmon anemia
Some Estimates of Losses due to Shrimp Diseases
1992 Thailand
1993 China
Viet Nam
1994 Thailand
India
1998 Australia
1999 Ecuador
1999 Panama
Global Estimate:
YHD
US$ 30.6 M
Shrimp Diseases
US$ 420 M
MBV, WSD,YHD
US$ 100 M
YHD,WSD
US$ 650 M
WSD
US$ 17.5 M
Shrimp diseases
US$ 32.5 M
WSD
US$ 280.5 M
WSD
US$ 40 M
US$ 3.019 Billion
YHD – Yellowhead Disease; MBV – Monodon Baculovirus; WSD – White Spot Disease
Impacts of Early Mortality Syndrome
(EMS) shrimp (bacterial aetiology)
 Viet Nam
 39000 hectares of shrimp farming areas (2010-2011)
 affected main shrimp producing provinces of VN
 Malaysia: USD 0.1 B (2011)
 Global Aquaculture Alliance estimate: USD 1 B
 Private sector: drop in profit between 50-70%
 Trade: suspension or ban of importation of live shrimp or
all forms of shrimp products from countries with EMS