Decapod iridescent Virus 1 (DIV1) infection,
Chinese Taipei
Information received on 09/07/2020 from Dr Wen-Jane Tu, Chief Veterinary Officer, Director General, Bureau of Animal and Plant Health Inspection and Quarantine, Council of Agriculture, Executive Yuan, Taipei, Chinese Taipei
Summary
Report type Immediate notification
Date of start of the event 18/05/2020
Date of confirmation of the event 20/05/2020
Report date 09/07/2020
Date submitted to OIE 09/07/2020
Reason for notification Emerging disease
Morbidity 13 %
Mortality 13 %
Zoonotic impact No
Causal agent Decapod iridescent virus 1 (DIV1)
Serotype Pending
New outbreaks (16)
Outbreak 1 (2020-8) Jiadong Township, Pingtung County
Date of start of the outbreak 18/05/2020
Outbreak status Resolved (13/06/2020)
Epidemiological unit Pond
Water type Fresh water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
redclaw crayfish (Cherax quadricarinatus) 0 % 0 % 60000 0 60000 0
Outbreak 2 (2020-3) Sanzhi District, New Taipei City
Date of start of the outbreak 25/05/2020
Outbreak status Continuing (or date resolved not provided)
Epidemiological unit Pond
Water type Brackish water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
whiteleg shrimp (Litopenaeus vannamei) 20 % 20 % 3400000 700000 700000 0 0
Outbreak 3 (2020-7) Tianliao District, Kaohsiung City
Date of start of the outbreak 26/05/2020
Outbreak status Resolved (15/06/2020)
Epidemiological unit Pond
Water type Fresh water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
redclaw crayfish (Cherax quadricarinatus) 0 % 0 % 96 0 96 0
Outbreak 4 (2020-9) Ligang Township, Pingtung County
Date of start of the outbreak 26/05/2020
Outbreak status Resolved (15/06/2020)
Epidemiological unit Pond
Water type Fresh water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
redclaw crayfish (Cherax quadricarinatus) 0 % 0 % 6000 0 6000 0
Outbreak 5 (2020-6) Citong Township, Yunlin County
Date of start of the outbreak 27/05/2020
Outbreak status Resolved (16/06/2020)
Epidemiological unit Pond
Water type Fresh water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
redclaw crayfish (Cherax quadricarinatus) 0 % 0 % 905620 0 905620 0
Outbreak 6 (2020-4) Zhubei City, Hsinchu County
Date of start of the outbreak 28/05/2020
Outbreak status Resolved (15/06/2020)
Epidemiological unit Pond
Water type Fresh water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
redclaw crayfish (Cherax quadricarinatus) 0 % 0 % 51240 0 51240 0
Outbreak 7 (2020-10) Ligang Township, Pingtung County
Date of start of the outbreak 28/05/2020
Outbreak status Resolved (13/06/2020)
Epidemiological unit Pond
Water type Fresh water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
redclaw crayfish (Cherax quadricarinatus) 0 % 0 % 100 0 100 0
Outbreak 8 (2020-11) Jiuru Township, Pingtung County
Date of start of the outbreak 28/05/2020
Outbreak status Resolved (16/06/2020)
Epidemiological unit Pond
Water type Fresh water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
redclaw crayfish (Cherax quadricarinatus) 0 % 0 % 1000000 0 1000000 0
Outbreak 9 (2020-12) Nanzhou Township, Pingtung County
Date of start of the outbreak 29/05/2020
Outbreak status Resolved (18/06/2020)
Epidemiological unit Pond
Water type Fresh water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
redclaw crayfish (Cherax quadricarinatus) 0 % 0 % 1000000 0 1000000 0
Outbreak 10 (2020-5) Mingjian Township, Nantou County
Date of start of the outbreak 29/05/2020
Outbreak status Resolved (19/06/2020)
Epidemiological unit Pond
Water type Fresh water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
redclaw crayfish (Cherax quadricarinatus) 0 % 0 % 4284 0 4284 0
Outbreak 11 (2020-13) Jiuru Township, Pingtung County
Date of start of the outbreak 30/05/2020
Outbreak status Resolved (16/06/2020)
Epidemiological unit Pond
Water type Fresh water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
redclaw crayfish (Cherax quadricarinatus) 0 % 0 % 1000000 0 1000000 0
Outbreak 12 (2020-14) Jiuru Township, Pingtung County
Date of start of the outbreak 01/06/2020
Outbreak status Resolved (20/06/2020)
Epidemiological unit Pond
Water type Fresh water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
redclaw crayfish (Cherax quadricarinatus) 0 % 0 % 310000 0 310000 0
Outbreak 13 (2020-15) Wujie Township, Yilan County
Date of start of the outbreak 02/06/2020
Outbreak status Continuing (or date resolved not provided)
Epidemiological unit Pond
Water type Brackish water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
whiteleg shrimp (Litopenaeus vannamei) 90 % 90 % 600000 540000 540000 0 0
Outbreak 14 (2020-16) Toucheng Township, Yilan County
Date of start of the outbreak 02/06/2020
Outbreak status Continuing (or date resolved not provided)
Epidemiological unit Pond
Water type Brackish water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
grass shrimp (Penaeus monodon) 20 % 20 % 100000 20000 20000 0 0
Outbreak 15 (2020-1) Sanzhi District, New Taipei City
Date of start of the outbreak 03/06/2020
Outbreak status Resolved (24/06/2020)
Epidemiological unit Pond
Water type Fresh water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
redclaw crayfish (Cherax quadricarinatus) 0 % 0 % 15000 0 15000 0
Outbreak 16 (2020-2) Sanzhi District, New Taipei City
Date of start of the outbreak 03/06/2020
Outbreak status Continuing (or date resolved not provided)
Epidemiological unit Pond
Water type Brackish water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
whiteleg shrimp (Litopenaeus vannamei) 0 % 0 % 1000000 0 0 0
Summary of outbreaks Total outbreaks: 16
Total animals affected
Species Susceptible Cases Deaths Killed and disposed of Slaughtered
redclaw crayfish (Cherax quadricarinatus) 4352340 ** 0 4352340 0
whiteleg shrimp (Litopenaeus vannamei) 5000000 1240000 ** 1240000 0 0
grass shrimp (Penaeus monodon) 100000 20000 20000 0 0
Outbreak statistics
Species Apparent morbidity rate Apparent mortality rate Apparent case fatality rate Proportion susceptible animals lost*
redclaw crayfish (Cherax quadricarinatus) ** 0.00% ** 100.00%
whiteleg shrimp (Litopenaeus vannamei) ** 24.80% ** 24.80%
grass shrimp (Penaeus monodon) 20.00% 20.00% 100.00% 20.00%
*Removed from the susceptible population through death, destruction and/or slaughter
**Not calculated because of missing information
Epidemiology
Source of the outbreak(s) or origin of infection
  • Unknown or inconclusive
Epidemiological comments Active surveillance was conducted for 103 shrimp farms from May 8 to 21 in 2020, and one redclaw crayfish (Cherax quadricarinatus) farm was confirmed with positive reaction to nucleic acid of Decapod iridescent virus 1 (DIV1). Due to the first detection of DIV1 case in Chinese Taipei, the Council of Agriculture immediately initiated a comprehensive monitoring of whiteleg shrimp (Litopenaeus vannamei) , grass shrimp (Penaeus monodon), giant river prawn (Macrobrachium rosenbergii), crab and all crawfish farms. At the same time, 2 whiteleg shrimp (Litopenaeus vannamei) farms and 1 grass shrimp (Penaeus monodon) farm were also confirmed with DIV1 infection. Active surveillance is still ongoing, and any positive result will be included in follow-up reports. As of June 17 2020, 12 redclaw crayfish farms, 3 whiteleg shrimp farms and 1 grass shrimp farm were positive for DIV1.
Control measures
Measures applied
  • Disinfection / Disinfestation
  • Screening
  • Traceability
  • Quarantine
  • Surveillance outside containment and/or protection zone
  • Official disposal of carcasses, by-products and waste
  • Stamping out
  • Control of vectors
  • Vaccination permitted (if a vaccine exists)
  • No treatment of affected animals
Measures to be applied
  • No other measures
Diagnostic test results
Laboratory name and type Species Test Test date Result
Animal Health Research Institute (National laboratory) grass shrimp (Penaeus monodon) gene sequencing 08/06/2020 Positive
Animal Health Research Institute (National laboratory) grass shrimp (Penaeus monodon) polymerase chain reaction (PCR) 08/06/2020 Positive
Animal Health Research Institute (National laboratory) grass shrimp (Penaeus monodon) real-time PCR 08/06/2020 Positive
Animal Health Research Institute (National laboratory) redclaw crayfish (Cherax quadricarinatus) gene sequencing 04/06/2020 Positive
Animal Health Research Institute (National laboratory) redclaw crayfish (Cherax quadricarinatus) gene sequencing 09/06/2020 Positive
Animal Health Research Institute (National laboratory) redclaw crayfish (Cherax quadricarinatus) polymerase chain reaction (PCR) 20/05/2020 Positive
Animal Health Research Institute (National laboratory) redclaw crayfish (Cherax quadricarinatus) polymerase chain reaction (PCR) 04/06/2020 Positive
Animal Health Research Institute (National laboratory) redclaw crayfish (Cherax quadricarinatus) polymerase chain reaction (PCR) 09/06/2020 Positive
Animal Health Research Institute (National laboratory) redclaw crayfish (Cherax quadricarinatus) real-time PCR 20/05/2020 Positive
Animal Health Research Institute (National laboratory) redclaw crayfish (Cherax quadricarinatus) real-time PCR 04/06/2020 Positive
Animal Health Research Institute (National laboratory) redclaw crayfish (Cherax quadricarinatus) real-time PCR 09/06/2020 Positive
Animal Health Research Institute (National laboratory) whiteleg shrimp (Litopenaeus vannamei) gene sequencing 09/06/2020 Positive
Animal Health Research Institute (National laboratory) whiteleg shrimp (Litopenaeus vannamei) polymerase chain reaction (PCR) 09/06/2020 Positive
Animal Health Research Institute (National laboratory) whiteleg shrimp (Litopenaeus vannamei) real-time PCR 09/06/2020 Positive
Future Reporting
The event is continuing. Weekly follow-up reports will be submitted.
Map of outbreak locations