White spot disease,
Australia
Information received on 21/04/2020 from Dr Mark Schipp, Chief Veterinary Officer, Department of Agriculture, Water and the Environment, Australian Government, Canberra, Australia
Summary
Report type Immediate notification (Final report)
Date of start of the event 06/04/2020
Date of confirmation of the event 15/04/2020
Report date 21/04/2020
Date submitted to OIE 21/04/2020
Date event resolved 21/04/2020
Reason for notification Recurrence of a listed disease
Date of previous occurrence 03/2018
Manifestation of disease Clinical disease
Causal agent White spot syndrome virus
Nature of diagnosis Laboratory (advanced)
This event pertains to a defined zone within the country
New outbreaks (3)
Outbreak 1 ( Moreton Bay wild surveillance) SE Queensland Movement Restriction Area, Moreton Bay, Queensland
Date of start of the outbreak 06/04/2020
Outbreak status Resolved (21/04/2020)
Epidemiological unit Coastal area
Water type Salt water
Population type Wild
Production system Open
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
Greasyback prawn (Metapenaeus ensis) 0 % 0 % 0 0
Brown tiger prawn (Penaeus esculentus) 0 (scale 0 to 5) 0 (scale 0 to 5) 0 0
Mangrove swimming crab (Thalamita crenata) 0 % 0 % 0 0
Affected population Part of routine six-monthly surveillance for wild crustaceans within the movement restriction area, the known infected zone.
Outbreak 2 (Farm A) SE Queensland Movement Restriction Area, Logan River, Queensland
Date of start of the outbreak 12/04/2020
Outbreak status Resolved (17/04/2020)
Epidemiological unit Pond
Water type Salt water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
Black tiger prawn (Penaeus monodon) 1 (scale 0 to 5) 1 (scale 0 to 5)
Outbreak 3 (Farm B) Queensland Movement Restriction Area, Logan River, Queensland
Date of start of the outbreak 14/04/2020
Outbreak status Resolved (17/04/2020)
Epidemiological unit Pond
Water type Salt water
Population type Farmed
Production system Semi-closed
Affected animals
Species Morbidity Mortality Susceptible Cases Deaths Killed and disposed of Slaughtered
Black tiger prawn (Penaeus monodon) 1 (scale 0 to 5) 0 (scale 0 to 5)
Summary of outbreaks Total outbreaks: 3
Total animals affected
Species Susceptible Cases Deaths Killed and disposed of Slaughtered
Greasyback prawn (Metapenaeus ensis) ** 0 0
Brown tiger prawn (Penaeus esculentus) ** 0 0
Mangrove swimming crab (Thalamita crenata) ** 0 0
Black tiger prawn (Penaeus monodon) **
Outbreak statistics
Species Apparent morbidity rate Apparent mortality rate Apparent case fatality rate Proportion susceptible animals lost*
Greasyback prawn (Metapenaeus ensis) ** ** ** **
Brown tiger prawn (Penaeus esculentus) ** ** ** **
Mangrove swimming crab (Thalamita crenata) ** ** ** **
Black tiger prawn (Penaeus monodon) ** ** ** **
*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 White spot syndrome virus (WSSV) has been detected in samples of wild crustaceans from two sites within the WSSV movement restriction area (MRA) in south east Queensland. The detections of WSSV were made during routine six-monthly surveillance. Samples collected from these two sites had last tested positive for WSSV in March 2018. Samples of prawns from two prawn farms located adjacent to the Logan River and also within the MRA have returned positive test results for WSSV. These farms were at the end of their production cycle and both farms are now destocked. Enhanced biosecurity measures are in place and planning for decontamination of the ponds is underway. This is the first detection of WSSV in prawn farms within the MRA since production resumed in 2018 following a WSSV outbreak in 2016. Restrictions on movement of crustaceans, fishing restrictions, biosecurity controls, and surveillance have been in place for the MRA since 16 March 2017 following the first detections of WSSV in the area in wild crustaceans. WSSV has not been detected in any area of Australia outside of the MRA despite a national surveillance program that has been ongoing for more than 2 years. Basic biosecurity conditions for infection with WSSV were reviewed following the 2016 outbreak in south east Queensland and have been in place continuously.
Control measures
Measures applied
  • Zoning
  • Disinfection
  • Process to inactivate the pathogenic agent in products or by-products
  • Killing for commercial use or own use
  • Control of wildlife reservoirs
  • Emergency harvest
  • Quarantine
  • Screening
  • Traceability
  • Surveillance within infected and/or protection zone
  • Surveillance outside infected and/or protection zone
  • Movement control inside the country
  • 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
Australian Centre for Disease Preparedness (National laboratory) Black tiger prawn (Penaeus monodon) polymerase chain reaction (PCR) 17/04/2020 Positive
Australian Centre for Disease Preparedness (National laboratory) Black tiger prawn (Penaeus monodon) real-time PCR 17/04/2020 Positive
Australian Centre for Disease Preparedness (National laboratory) mangrove swimming crab (Thalamita crenata) polymerase chain reaction (PCR) 15/04/2020 Positive
Australian Centre for Disease Preparedness (National laboratory) mangrove swimming crab (Thalamita crenata) real-time PCR 15/04/2020 Positive
Biosecurity Sciences Laboratory (Regional Laboratory) Black tiger prawn (Penaeus monodon) real-time PCR 12/04/2020 Positive
Biosecurity Sciences Laboratory (Regional Laboratory) Mangrove swimming crab (Thalamita crenata) real-time PCR 06/04/2020 Positive
Future Reporting
The event is resolved. No more reports will be submitted.
Map of outbreak locations