Department of Livestock Development
Ministry of Agriculture of Cooperatives, Thailand



Overall operation


Highly pathogenic avian influenza (HPAI) is a List A disease according to the OIE. Because of its highly pathogenic nature and destructive impact on poultry production and trade, the overall policy is eradication of the disease in the shortest period as possible to minimize all potential damages. HPAI is enlisted by the Ministry of Agriculture and Cooperatives as a highly contagious disease under the Animal Epidemic Act B.E.2499 (AC 1956) and its reversion in B.E. 2542 (AC1999), which allows strategic actions of stamping-out, movement control, quarantine, compensation, and other necessary measures possible.
January,2004 is the first time that highly pathogenic avian influenza outbreak occurred in Thailand. HPAI was detected in a layer farm, Bangplama district, Suphanburi province, central region of Thailand. The emergency plan for highly contagious avian diseases was launched immediately, all necessary measures and operations have been implemented. Details of the operations, which emphasize on stamping-out strategy, are summarized as follow.

1. Pre-emptive culling: Depopulation of chicken in farms and backyard chickens in the area within 5-kilometer radius from the infected farm, followed by disinfecting of the premises.

2. Surveillance during the outbreak: The area within 50 kilometers from infected farm is on intensive surveillance. Any positive farms will be depopulated and disinfected.

3. Movement control: Movement of avian species from the area within 60-kilometer radius is not allowed for at least 30 days.

4. Public awareness campaign: Information, recommendation and guidelines are distributed to facilitate cooperation and create good understanding from industry and the community.

After stamping-out of the last affected premise the following plans will be executed in order to assure freedom from disease and, later, to monitor the existence of the virus and early detection of disease.

Tracing and surveillance: After repopulation of the affected areas, surveillance will be carried out for 5 months to confirm freedom from disease.

Surveillance and monitoring: After freedom from disease is assured active and passive surveillance for AI will be carried out in order to obtain epidemiological information for prevention and control.

Emergency Response for Avian Influenza Outbreak

Outline of this document

Phase I : During the outbreak
page 3

  Policy and strategies
3
  Case definition
3
  The operation
     - Pre-emptive stamping-out
     - Surveillance during the outbreak
     - Movement control
     - Public awareness
3
3
3
4
4
  Public awareness campaign
5


Phase II : Post-outbreak
5

  Principle and strategy
5
  Post-outbreak surveillance
5


Phase III : Long term surveillance and monitoring
6

  Principle and strategy
6
  National surveillance plan for avian influenza
6

The Sanitary Chicken Project
Appendix 1
The National Surveillance Plan for AI
Appendix 2
Results of AI surveillance 1997-2002 (publication)
Appendix 3

 

Phase I : During the outbreak

Policy and strategies
Highly pathogenic avian influenza (HPAI) is a disease in List A of Office of International Epizooties (OIE) because of its highly pathogenic nature and destructive impact on trade. The policy set by the Department of Livestock Development, Ministry of Agriculture and Cooperatives is eradication of the disease as fast as possible to minimize potential damages. HPAI is enlisted in the highly contagious diseases under the Animal Epidemic Act B.E. 2449 (A.C. 1956) and its reversion in B.E. 2542 (A.C.1999), which allows strategic actions of stamping-out, quarantine, movement control, compensation and other necessary measures possible.

Case definition
These criteria are established in order for early detection of the disease. Target animals include chicken, duck, quail and other avian species presented with the following clinical signs.
1. Severe respiratory signs with excessively watery eyes and sinusitis, cyanosis of the combs, wattle and shanks, edema of the head, ruffled feathers
2. Diarrhea and nervous signs
3. No noticeable signs but sudden death of almost 100%, or cumulative death approximately 40% within 3 days

If one of the above criteria is observed, the disease control measures must be executed immediately.

The operation
- Pre-emptive stamping-out If suspected case is identified, that premise will be quarantined. Samples will be collected and analyzed for avian influenza and other possible pathogens. If HPAI is confirmed, that particular premise will be depopulated and disinfected. All premises within 5-kilometer radius from the index farm will be depopulated and disinfected.
- Surveillance during the outbreak The area within 50 kilometers from infected farm is on intensive surveillance. Cloacal swabs will be collected and analyzed for the virus. If the virus is detected that infected farm will be depopulated and disinfected. Other premises in this zone (50 km. radius) are on quarantine.
- Movement control Movement of avian species and their products from the area within 60-kilometer radius from infected farms are prohibited. Checkpoints will be set up by the DLD to enforce the regulations.
- Public awareness campaign Information, recommendations and guidelines will be distributed to private sector, risk groups and general public to raise awareness and good understanding of the community.

Phase II : Post-outbreak

Principle and strategy
Repopulation of affected areas will be considered if no new case or death is detected 21 days after destruction of the last affected premise. If repopulation is allowed surveillance will be carried out for 5 months to confirm freedom from disease.

Post-outbreak surveillance
Surveillance in the areas other than control zone (50 km. radius) includes testing of the flocks that show any clinical signs fit in the case definition. Virological and/or serological investigations will be conducted.

For control zone, sample collection for virological assays will be carried out in flocks at 30 days after repopulation, before selling and/or at 5 months to establish a 95% confidence of detecting infection in the flocks at less than 5%. Examination for AI includes twice weekly clinical examinations for 30 days then every two-week for 5 months, identification of virus or other pathogen will be performed on dead birds. Positive flock, if any, will be depopulated and disinfected. Necessary measures will be undertaken immediately to control the disease.

Post-outbreak surveillance entitled Sanitary chicken project is attached as appendix 1.

Phase III : Long term surveillance and monitoring

Principle and strategy
Highly pathogenic avian influenza (HPAI) had never been reported in Thailand until January, 2004. Although, active and passive surveillance have been conducted since 1997 HPAI outbreak was unexpectedly occurred and spread widely (see appendix 3 for the publication). Stamping-out strategy was executed however carrier birds or migratory birds cannot be completely destroyed. For these reasons epidemiological information is very crucial in order for early detection of the disease. This objective can only be achieved by strengthening of surveillance.

National surveillance plan for avian influenza
National surveillance plan for AI is a long tern project which composed of active and passive surveillance. Budget will be granted by the Government annually.
Description of the plan is attached as appendix 2.

Bureau of Disease Control and Veterinary Services  

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