USDA recently authorized the emergency use of ventilation shutdown (VSD) to depopulate poultry flocks affected by avian influenza. The federal agency approved the conditional use of VSD because traditional depopulation methods did not always kill affected birds quickly enough to control the spread of the virus as effectively as desired.

However, special criteria must be met before ventilation shutdown may be used. These are the 6 requirements that must be met:

1. Other depopulation methods are unavailable – More traditional depopulation methods may not be available, or available in a timely manner.

2. High threat of transmission – In some cases, the amplification of the avian influenza virus on the premises could pose a significant threat for further transmission and ongoing spread of the virus.


3. Review by veterinary officials – The Ventilation Shutdown Evidence and Policy document must be reviewed and discussed by officials from USDA's Animal and Plant Health Inspection Service (APHIS), state and/or tribal officials and the Incident Management Team (IMT) before VSD may be utilized.

4. Incident Management Team approval – The IMT must determine that VSD is the most appropriate depopulation method available.

5. State approval – The state animal health official or a designee must concur with the IMT that VSD is the best depopulation method available.

6. National Incident Coordinator approval – The National Incident Coordinator, or a designee, must also agree that ventilation shutdown is the best depopulation method to be used.