African horse sickness,
Information received on 24/04/2020 from Dr Sorravis Thaneto, Director General, Livestock Development, Ministry of Agriculture and Cooperatives, BANGKOK, Thailand
Report type Follow-up report No. 4
Date of start of the event 24/02/2020
Date of confirmation of the event 27/03/2020
Report date 24/04/2020
Date submitted to OIE 24/04/2020
Reason for notification First occurrence of a listed disease in the country
Causal agent African horse sickness virus
Serotype 1
Nature of diagnosis Clinical, Laboratory (advanced)
This event pertains to a defined zone within the country
Related reports Immediate notification (27/03/2020)
Follow-up report No. 1 (03/04/2020)
Follow-up report No. 2 (10/04/2020)
Follow-up report No. 3 (17/04/2020)
Follow-up report No. 4 (24/04/2020)
Follow-up report No. 5 (01/05/2020)
Follow-up report No. 6 (08/05/2020)
Follow-up report No. 7 (15/05/2020)
Follow-up report No. 8 (22/05/2020)
Follow-up report No. 9 (29/05/2020)
Follow-up report No. 10 (05/06/2020)
Follow-up report No. 11 (12/06/2020)
Follow-up report No. 12 (19/06/2020)
Follow-up report No. 13 (26/06/2020)
Follow-up report No. 14 (03/07/2020)
Follow-up report No. 15 (10/07/2020)
Follow-up report No. 16 (17/07/2020)
Follow-up report No. 17 (24/07/2020)
Follow-up report No. 18 (31/07/2020)
Follow-up report No. 19 (07/08/2020)
Follow-up report No. 20 (14/08/2020)
Follow-up report No. 21 (21/08/2020)
Follow-up report No. 22 (28/08/2020)
Follow-up report No. 23 (04/09/2020)
Follow-up report No. 24 (11/09/2020)
Follow-up report No. 25 (18/09/2020)
Follow-up report No. 26 (25/09/2020)
Follow-up report No. 27 (02/10/2020)
Follow-up report No. 28 (14/10/2020)
Follow-up report No. 29 (16/10/2020)
Follow-up report No. 30 (26/10/2020)
Follow-up report No. 31 (30/10/2020)
Follow-up report No. 32 (06/11/2020)
Follow-up report No. 33 (14/11/2020)
Follow-up report No. 34 (23/11/2020)
Follow-up report No. 35 (27/11/2020)
Follow-up report No. 36 (04/12/2020)
Follow-up report No. 37 (15/12/2020)
Follow-up report No. 38 (21/12/2020)
Follow-up report No. 39 (04/01/2021)
Follow-up report No. 40 (07/01/2021)
Follow-up report No. 41 (13/01/2021)
Follow-up report No. 42 (21/01/2021)
New outbreaks (1)
Outbreak 1 Mueang Sa Kaeo, Sa Kaeo, Mueang Sa Kaeo, Sa Kaeo
Date of start of the outbreak 14/04/2020
Outbreak status Resolved (25/05/2020)
Epidemiological unit Farm
Affected animals
Species Susceptible Cases Deaths Killed and disposed of Slaughtered
Equidae 22 4 3 0 0
Affected population Species of horses of different ages and sexes.
Summary of outbreaks Total outbreaks: 1
Total animals affected
Species Susceptible Cases Deaths Killed and disposed of Slaughtered
Equidae 22 4 3 0 0
Outbreak statistics
Species Apparent morbidity rate Apparent mortality rate Apparent case fatality rate Proportion susceptible animals lost*
Equidae 18.18% 13.64% 75.00% 13.64%
*Removed from the susceptible population through death, destruction and/or slaughter
Source of the outbreak(s) or origin of infection
  • Unknown or inconclusive
Epidemiological comments Four samples (equine blood and serum) were sent to the Pirbright Institute (United Kingdom) for checking serotype on the 31st March 2020 and the results were positive for African Horse Sickness (AHS) disease and all four samples were diagnosed as serotype 1 of AHS virus. Those samples were sent by a private veterinarian. However, the Department of Livestock Development (DLD, competent authority of veterinary service in Thailand) will send more samples from other outbreak spots to check the serotype in two or more OIE Reference Laboratories for AHS soon. The Department of Livestock Development started vaccination against African Horse Sickness (Polyvalent live attenuated vaccine) on April 19, 2020. Horses within the Horse and Animal Breeding Station, Thai Red Cross Society, Cha-am District, Phetchaburi Province, supplying 560 horses used to produce immunoglobulins to treat rabies and snake venom, were the first one to be vaccinated with AHS vaccine in Thailand. The further AHS vaccination started from April 20, 2020 which will be conducted for horses at a distance of 50 kilometers from the disease sites in 7 provinces where an outbreak was discovered. The AHS working group conducted a preparatory meeting with targeted Regional, Provincial, and District Livestock offices and related parties before the vaccination. The meeting emphasized on the operation for effective vaccination to struggle against the AHS epidemic as quickly as possible.
Control measures
Measures applied
  • Movement control inside the country
  • Vaccination in response to the outbreak (s)
    Administrative division Species Total Vaccinated Details
    Phetchaburi Equidae 560
  • Surveillance outside containment and/or protection zone
  • Surveillance within containment and/or protection zone
  • Quarantine
  • Zoning
  • Disinfection
  • Control of vectors
  • Vector surveillance
  • Treatment of affected animals ( Anti-inflammation, antibiotics, antipyretic and supplement)
Measures to be applied
  • No other measures
Diagnostic test results
Laboratory name and type Species Test Test date Result
National Institute of Animal Health (National laboratory) Equidae polymerase chain reaction (PCR) 03/04/2020 Positive
National Institute of Animal Health (National laboratory) Equidae real-time reverse transcriptase/polymerase chain reaction (RRT-PCR) 13/04/2020 Positive
National Institute of Animal Health (National laboratory) Equidae real-time reverse transcriptase/polymerase chain reaction (RRT-PCR) 15/04/2020 Positive
National Institute of Animal Health (National laboratory) Equidae reverse transcription - polymerase chain reaction (RT-PCR) 07/04/2020 Positive
National Institute of Animal Health (National laboratory) Equidae serotyping 15/04/2020 Positive
The Pirbright Institute (OIE Reference Laboratory) Equidae reverse transcription - polymerase chain reaction (RT-PCR) 04/04/2020 Positive
Future Reporting
The event is continuing. Weekly follow-up reports will be submitted.
Map of outbreak locations