How is avian influenza getting into barns? Researchers in Canada and other poultry-producing countries continue to search for answers to this, as we near 4 years of the current outbreak.

This past summer, Canadian Food Inspection Agency (CFIA) veterinarians visited farms that had experienced avian influenza outbreaks more than once, to look at potential risk factors for introduction of the virus. Visits were conducted on 13 farms in total, and covered all commercial production types (broilers, specialty chickens, ducks, turkeys, layers, broiler breeder).

Here’s a list of potential risk factors and methods to reduce that risk:

Barn entrance process

Highest risk: Barn that had no barn-dedicated boots.

Medium risk: Barn entrances with either no delimitation or a painted line between the CAZ and the RA. Some Personal Protective Equipment (PPE), such as coveralls, hand sanitizer, or gloves are available.

Lowest risk: The barn entrance had a bench to separate the CAZ and the RA and had available PPE.

• Disinfectant sprays or footbaths were seen on multiple farms, but the were not used effectively (short contact time, exposure to sunlight, contained organic material, or not replaced frequently enough)

Mortality management – mortality collection bucket

Highest risk: Mortalities are taken outside the barn while wearing barn dedicated boots, or the same bucket is being used in all barns and then taken to the disposal site.

Medium risk: Mortalities are collected in barn-specific buckets and then taken outside for disposal.

Lowest risk: Mortalities are collected in barn-specific buckets and then the mortality is transferred from the inside barn bucket to an outdoor bucket for disposal.

Mortality management – composting

Highest risk: Mortality is buried in an unprotected manure pile, such as an open shed, that can be accessed by wildlife.

Medium risk: Mortality is buried in a protected manure pile with limited access by wildlife.

Lowest risk: Mortality is disposed of in a closed composter or incinerator, with no access by wildlife.

Shipping management

Highest risk: Protocols were the thinning-out and split loads took place over a period greater than 2 days

Lowest risk: All-out protocols are used.

• If thinning is used, cleaning and disinfecting the anteroom after thinning is a best practice, along with catching crew using PPE.

 

With ongoing avian influenza challenges and the virus continually being detected in wildlife, it’s important to be thinking critically about all the potential ways the virus could enter the barn.

Studies are on-going in British Columbia to look at the effectiveness of different air filtration systems, and the role of wind in transmitting avian influenza within and between farms. Researchers in Calgary are also looking into the mode of introduction of avian influenza onto farms, including the role of airborne spread. In Ontario and Quebec, researchers are doing a case control study on infected and non-infected turkey premises to identify risk factors for transmission. As results become available from these studies, we will be sure to share them.