USDA Finds Risk Factors for Avian Influenza in Current Outbreak

Dec 16, 2023

USDA has identified the biggest biosecurity risks at farms infected during the current avian influenza outbreak.

Many of the risk factors were unsurprising, such as having waterfowl near the poultry house, or being in a control zone for a nearby farm with avian influenza.

"If it's in your area, if it's in surrounding flocks or it's in surrounding wild birds, you are at increased risk," said Amy Delgado, director of USDA's Center for Epidemiology and Animal Health.

Delgado presented the results of the agency's research in a May 31 webinar.

One risk factor was low frequency of vehicle washing. Even if the farm doesn't have a permanent wash station, increased cleaning can help, Delgado said.

Another concern was not having personnel dedicated to a specific barn. It's not ideal for workers to move between barns or have the potential to go to any barn, Delgado said.

The lack of a farm entrance gate also came up as a risk factor. Gates could be a proxy for a variety of biosecurity practices, such as limiting farm visitors and implementing on-farm traffic patterns that reduce risk.

"Not that having a gate is somehow magical, but having a farm entrance gate probably represents a lot of infrastructure," Delgado said.

Other risk factors included sharing trucks or trailers with other farms, not mowing frequently, sending dead birds for rendering, and having rodent problems.

Some of those situations might represent reduced maintenance that could attract or admit wild birds, Delgado said.

Wild birds are the reservoir of avian influenza, and USDA found farms could protect themselves by cleaning up feed spills immediately and keeping feed out of reach for wild birds.

"If they have any access to feed, even if it's just sometimes, (that) really increases the odds of becoming infected," Delgado said.

Improvements to barn ventilation and efforts to deter wild birds often helped protect a farm from infection, she said.

USDA studied layers and turkeys using case control studies, which compare the experiences of infected and nearby non-infected farms.

Avian influenza has killed more than 58 million birds since February 2022. The U.S. has no active control areas around farms, but the disease remains a threat.

Find out more here.

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Phil Gruber is the news editor at Lancaster Farming. He can be reached at 717-721-4427 or [email protected]. Follow him @PhilLancFarming on Twitter.