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AVT session 2: Depopulation Strategies


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This second presentation of a series of 6 AVT presentation on Emergency Response to outbreaks of Avian Influenza focuses on depopulation strategies, rapid response management, culling, storage, transportation, composting and disposal of carcasses.

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AVT session 2: Depopulation Strategies

  1. 1. Harm Kiezebrink Research Fellow Faculty of Veterinary Science Queensland University
  2. 2. Depopulation  Rapid response management  Culling  Storage  Transportation  Composting  Disposal 2 © 2014 Applied Veterinary Technologies Europe AB
  3. 3. Incident Command System Structure 3 © 2014 Applied Veterinary Technologies Europe AB
  4. 4. Incident Command System  Clear management structure  Veterinary officer, responsible for veterinary tasks, including diagnose & sampling, animal welfare, reporting & clearance management  Non- veterinary field response manager, responsible for all non- veterinary tasks, including culling, cleaning & disinfection & logistics  Health & Safety officer supervising the human health during the operation, including Occupational Health & Safety, gate management  Administration & Finance officer supervising the financial management, registration and communication processes  Clear - enforceable - instructions instead of on-the-job training  Each farm needs its own outbreak response plan 4 © 2014 Applied Veterinary Technologies Europe AB
  5. 5. Culling Official definitions  According to the OIE  Carrying out under the vet authority, the killing of animals infected and suspected to be infected  According to the FAO  Designation of clean & infected zones  Intensive disease surveillance within the infected zone  Quarantine of livestock movement  Immediate slaughter and disposal of all susceptible animals (depopulation) 5 © 2014 Applied Veterinary Technologies Europe AB
  6. 6. Culling - Animal Welfare - Animal suffering increases contamination risks  Birds sweat extremely when they are killed under stressed conditions  Sweating causes the skin and feathers to be wet, creating the perfect environment for viruses containment  Viruses hidden under feathers Animal cruelty upsets people  International protests  Negative impact on consumption of poultry products 6 © 2014 Applied Veterinary Technologies Europe AB
  7. 7. 7 Summarizing Strategy What needs to be achieved  Depopulate within 24-48 hours  Use the most appropriate culling method:  Killing humanly, according to the International standards  Limited number of operators and easy to operate  Limited exposure between responders and animals  Use the technique that fits the outbreak situation  Create an outbreak response plan for each farm location in advance © 2014 Applied Veterinary Technologies Europe AB
  8. 8. Poultry Killing Methods - Recommended by OIE - 4 generic categories:  Physical  Chemical  Electrical  Gaseous agents  CO2 gas stunning  Anoxia method (high expansion foam filled with 100% Nitrogen) Not recommended by the OIE:  Low expansion fire fighting foam 8 © 2014 Applied Veterinary Technologies Europe AB
  9. 9. Physical stunning 9 © 2014 Applied Veterinary Technologies Europe AB
  10. 10. Electrical stunning 10 © 2014 Applied Veterinary Technologies Europe AB
  11. 11. CO2 gas stunning Large-scale 1.100 liter containers © 2014 Applied Veterinary Technologies Europe AB
  12. 12. CO2 gas stunning Alternative container systems 12 © 2014 Applied Veterinary Technologies Europe AB
  13. 13. CO2 gas stunning Stable gassing 13 © 2014 Applied Veterinary Technologies Europe AB
  14. 14. Wet foam stunning Fire fighting foam 14 © 2014 Applied Veterinary Technologies Europe AB
  15. 15. High expansion Nitrogen foam The Anoxia method  High expansion foam bubbles, created under low pressure condition  kills by Anoxia – total absence of Oxygen under atmospheric circumstances  nitrogen and the water/soap solution are mixed in a foam nozzle  Suitable for all sorts of mammals and types of housing Picture 15.4 Picture 15.2 Picture 15.3 Picture 15.5 Picture 15.6 Picture 15.1 15 © 2014 Applied Veterinary Technologies Europe AB
  16. 16.  Carcasses and dead birds  Feed stock  Eggs and egg trays  Litter and beddings  Manure  Organic waste products  Organic building materials impossible to decontaminate  Disposables used during the response operation 16 Contaminated materials - Organic materials & disposables - © 2014 Applied Veterinary Technologies Europe AB
  17. 17. Managing contaminated materials All contaminated materials must be • Collected and conserved to prevent contamination • Stored until further processed; transported to disposal location • Safely disposed 17 © 2014 Applied Veterinary Technologies Europe AB
  18. 18. Collection & conservation  Although the virus reproduction stops after the birds are culled, they maintain a serious threat:  Spray a soapy water over all materials and wait 24 hours before the next disposal phase can start  Viruses survive in organic materials, contaminated water, dust on the feathers, cages, troughs, and manure belts  Soap helps to break down the virus load on the infected materials 18 © 2014 Applied Veterinary Technologies Europe AB
  19. 19. Temporary storage Temporary storage of contaminated materials impose risks  When the farm is located within a densely populated area  When the distance between farm and disposal area becomes critical for timely response  When there are large volumes of contaminated materials on the farm 19 © 2014 Applied Veterinary Technologies Europe AB
  20. 20. 20 Temporary cold store on the farm  Minimizing risks of virus reintroduction  Package infected materials in 1 M3 disposable containers on pallets  Freeze /store the materials safely on side until safe disposal can be guaranteed  Safe handling & transporting frozen plastic bags  Frozen contaminated plastic bags are hard to rip open  Materials on pallets are simple and easy to handling logistically © 2014 Applied Veterinary Technologies Europe AB
  21. 21. Considerations to on site storage - use disposable containers - Contaminated materials need to be prepared for safe transportation: use disposable containers for this purpose  Use heavy duty plastic bags with a maximum capacity of 1 m3  Place the plastic bags in a disposable container and place the container on a disposable pallet  Fill the container with contaminated materials  Ziploc the plastic bag after it is full  Remove the disposable container  Disinfect the enclosed plastic bag and the disposable pallet  Store the pallet safely until further handling 21 © 2014 Applied Veterinary Technologies Europe AB
  22. 22. Incineration Picture 18.1  There are three broad categories of incineration techniques currently in use:  Open-air burning  Fixed-facility incineration  Air-curtain incineration  Follow site’s fire safety procedures.  Ensure local Fire Department is aware of any open burning.  Wear PPE issued by your supervisor including respirator and proximity suit.  Follow the site’s heat stress reduction plan.  Additional training is required when using fire extinguishers.  Air-curtains present significant risks, stay back from the edge! Air-curtain incineration 22 © 2014 Applied Veterinary Technologies Europe AB
  23. 23. Rendering  Rendering is the heating of material (carcasses) that simultaneously dries and separates the materials. A fatty substance (such as lard grease) and ground material is produced.  Rendering can inactivate the AI virus.  Rendering is a limited option as it increases the AI exposure risk for transportation workers and rendering plant personnel, and the potential to spread the virus to other locations. 23 © 2014 Applied Veterinary Technologies Europe AB
  24. 24. Burial There are three burial techniques that may be used:  Trench burial  Mass burial sites  Landfill  Hazards associated with burial include excavation hazards and heavy equipment issues. Know the hazards of your excavation!  Environmental contamination may result from disposal so a disposal decision support tool should be used when selecting burial method. 24 © 2014 Applied Veterinary Technologies Europe AB
  25. 25. Burial Controlling Excavation Hazards 25 © 2014 Applied Veterinary Technologies Europe AB
  26. 26. Composting Phase One:  Biological activity breaks down carcasses  The temperature of the compost pile increases and inactivates the AI virus  Soft tissue decomposes  Bones partially soften Phase Two:  The remaining materials (mainly bones) break down fully  The compost turns to a consistent dark brown to black soil or “humus” with a musty odor containing primarily non- pathogenic bacteria and plant nutrients Carcass composting is a natural biological process. 26 © 2014 Applied Veterinary Technologies Europe AB
  27. 27. Question and Answer Reflection: What’s on your mind?  27 27 © AVT Applied Veterinary Technologies Europe AB Address details: c/o INTRED, Södra Hamnen 2, 45142 Uddevalla, Sweden 556792-1944 - Phone: +44 7452 272 358- E-mail: