Tilapia lake virus disease,
Chinese Taipei
Information received on 14/06/2017 from Dr Tai-Hwa Shih , Chief Veterinary Officer, Deputy Director General, Bureau of Animal and Plant Health Inspection and Quarantine, Council of Agriculture Executive Yuan, Taipei 10070, Chinese Taipei
Summary
Report type Immediate notification
Date of start of the event 01/06/2017
Date of confirmation of the event 12/06/2017
Report date 13/06/2017
Date submitted to OIE 14/06/2017
Date event resolved 11/07/2017
Reason for notification Emerging disease
Morbidity 6.4 %
Mortality 6.4 %
Zoonotic impact No
Causal agent Tilapia lake virus (TiLV)
Related reports Immediate notification (13/06/2017)
Follow-up report No. 1 (11/08/2017)
New outbreaks (1)
Outbreak 1 Pond, Guanyin district, Taoyuan City
Date of start of the outbreak 01/06/2017
Outbreak status Resolved (26/06/2017)
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
Tilapia (Oreochromis niloticus x O. aureus) 6.4 % 6.4 % 150000 9600 9600 0 0
Affected population Tilapia(8-22)
Summary of outbreaks Total outbreaks: 1
Total animals affected
Species Susceptible Cases Deaths Killed and disposed of Slaughtered
Tilapia (Oreochromis niloticus x O. aureus) 150000 9600 9600 0 0
Outbreak statistics
Species Apparent morbidity rate Apparent mortality rate Apparent case fatality rate Proportion susceptible animals lost*
Tilapia (Oreochromis niloticus x O. aureus) 6.40% 6.40% 100.00% 6.40%
*Removed from the susceptible population through death, destruction and/or slaughter
Epidemiology
Source of the outbreak(s) or origin of infection
  • Unknown or inconclusive
Epidemiological comments The owner of a tilapia farm in Taoyuan City found abnormal mortality (approximately 6.4%) in his farmed tilapia since 1 June 2017, and then reported the event to the Local Disease Control Center on 6 June 2017. Samples from tilapia with dermal and ocular lesions were collected and sent to the National Laboratory (Animal Health Research Institute) for diagnosis. On 12 June 2017, RT-PCR results showed positive reaction to nucleic acid of Tilapia Lake Virus (TiLV) in those samples. Preliminary genetic and phylogenetic analyses of the genomic sequence of segment 3 gene showed the virus shared 93% and 92% identity with the strains found in Israel in 2014 and Thailand in 2016, respectively. Movement restriction of the index farm has been carried out after the confirmation of TiLV infection. Epidemiological investigation and surveillance of surrounding tilapia farms are being conducted.
Control measures
Measures applied
  • Disinfection / Disinfestation
  • Screening
  • Traceability
  • Quarantine
  • Surveillance outside containment and/or protection zone
  • Official disposal of carcasses, by-products and waste
  • 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) Tilapia (Oreochromis niloticus x O. aureus) reverse transcription - polymerase chain reaction (RT-PCR) 12/06/2017 Positive
Future Reporting
The event is continuing. Weekly follow-up reports will be submitted.
Map of outbreak locations