5 January 2023

4 minute read

By: USDA APHIS | Iowa State University

Editor's Note: The following content is an excerpt from Poultry Industry Manual: The Foreign Animal Disease Preparedness and Response Plan (FAD PReP)/National Animal Health Emergency Management System (NAHEMS) Guidelines which is designed to provide a framework for dealing with an animal health emergency in the United States. Additional content from the manual will be provided as an article series.

Containment areas consist of the infected premises (flock/farm), the Control Area, and the buffer-surveillance zone. While illustrated as concentric circles of approximately 2 miles (3.2 km) for the control zone and an additional 4 miles (6.4 km) for the buffer-surveillance zone in guidelines, they actually conform to the geography, political boundaries, and movements within the company or companies with the affected farm or farms in contact or close proximity to it. Criteria for issuing permits which allow movement of products within, between, or out of zones, need to be in place and agreed on prior to an outbreak. As a rule, nothing moves on or off a farm with a known or suspected infected flock except what is essential for disposing of the flock and subsequent cleaning and disinfection.

Litter and Manure

Houses are closed and litter containing the manure remains in the house for at least 2 weeks after depopulation. If possible, heating the house is done to accelerate destruction of the virus. Moving litter right after a diseased flock has been removed puts other flocks at risk, as viable virus is still present in the litter. Avian influenza viruses are destroyed in litter by heating to 135°F (56°C) for 90 minutes or 140°F (60°C) for 10 minutes. Composting litter in the house, which results in temperatures higher than those needed to destroy avian influenza virus is recommended, especially if it is combined with in-house composting of dead birds. A negative test of the litter for viable AI virus may be required prior to it being permitted for removal from the house. When litter is removed, it must be transported in covered trucks that are thoroughly cleaned and disinfected afterwards. Regulations for litter application on land remain unchanged.

Residual Feed

Residual feed from an infected flock is removed from the feed lines, hoppers, and bins and added to the litter. It cannot be removed from the farm or used to feed other birds. Feed may be transferred from a flock that has tested negative to another flock within the same containment zone, but not outside the containment area.

Mortalities

Mass euthanasia is done using carbon dioxide, although fire foam is showing promise as a better method (Rankin, 2010).

Catastrophic losses, regardless of if they are from heat, accidents, weather events, END, or HPAI, require extraordinary measures. Permission to bury or incinerate large numbers of birds because of an emergency may be granted, but more often, these measures remain unavailable. Movement to a landfill where carcasses will be buried is an option, but not all landfills accept animal disposal and the costs of transporting and using the landfill may be high. Information on possible use of landfills needs to be determined prior to a crisis.

A cost-effective method is in-house composting, which can be used when birds die or are euthanized in the house. Birds are piled into one or more rows down the middle of the house, covered with at least 2 feet of litter, and left for 2 weeks. It is recommended that daily temperatures be taken using a probe to be sure composting is occurring. Composting temperatures are sufficient to kill most infectious agents. When the temperature of the mortality compost drops, it is turned in the house to aerate the compost, or it is removed to a secondary composting facility on the farm where the process can be continued until it is complete. Sampling the compost and negative tests for HPAI or END viruses may be required before it can be removed from the house. Cleaning and disinfection of the house are done after the compost has been removed from the house.

Reference: "USDA APHIS | FAD Prep Industry Manuals". Aphis.Usda.Gov. 2013. https://www.aphis.usda.gov/aph...

The manual was produced by the Center for Food Security and Public Health, Iowa State University of Science and Technology, College of Veterinary Medicine, in collaboration with the USDA Animal and Plant Health Inspection Service through a cooperative agreement.