Author: Gary K. Felton, Associate Professor, Environmental Science and Technology, University of Maryland, gfelton@umd.edu

The regulatory answer varies from state to state. Conceptually, appropriate handling of a flock that is infected with AI is to euthanize the flock immediately, restrict access to the property, and inactivate the virus. Maryland’s approach has been to use a trained team to euthanize the flock, use pre-screened contractors to provide raw materials and services to compost the flock inside the poultry house, and simultaneously heat the house for an extended period of time. What follows is an explanation of why each step is important and what each step accomplishes.

Obviously, immediate euthanasia stops the host flock from growing more AI virus and from moving, which can release the virus into the air or onto dust. The trained team is necessary because biosecurity in the face of a high path virus is not something that can be explained in a short orientation. Restricting access to the property limits human transport vectors (trucks and people, etc.) to other farms and wild birds. Pre-screened contractors have been trained to sanitize their equipment and are selected from contractors that do NOT work on a poultry facility, thereby reducing the probability of bringing home the AI virus.

Composting heats the dead birds up to approximately 145° to 150°F and maintains that temperature for up to 14 days. Heat inactivation of the AI virus occurs at 131° to 145°F (Durham, 2006). The physical actions of building the compost windrow are confined to the poultry house, which reduces the opportunity for AI to escape into the environment. The dead birds are separated from scavengers by remaining in the poultry house, so the scavenger vector for disease transmission is eliminated. Heating the poultry house to between 90° and 105°F helps the composting process, but the hot, and more importantly dry, conditions in the poultry house help to deactivate the AI virus (Tiwari et al. 2006). As a result, the compost contains no AI, and the poultry tested completely free of AI. After 4 to 6 weeks, the compost is moved outside and covered to finish the composting process. The final product presents no health threat to humans or any avian species.

Additional reading:
Durham, S. 2006. Heat inactivates avian influenza and Newcastle disease in egg products. Agricultural Research February 2006:21.
Tiwari, A., D.P. Patnayak, Y. Chandler, M. Parsad, S.M. Goyal. 2006. Survival of two avian respiratory viruses on porous and nonporous surfaces. Avian Diseases 50:284-287.