Preparing For Avian Flu, USDA Has Vaccine For Chickens

Jul 27, 2015

By Allison Floyd

It’s not a question whether avian influenza will spread this fall. The questions are when the outbreak will begin and how prepared the industry will be to fight the disease.

Agriculture Secretary Tom Vilsack updated House Ag Committee members about the flu outbreak last week during a State of the Department address. Next week, USDA will meet with producers in Iowa, which was hit hard by the virus in spring and is expected to face more cases in fall.

Meanwhile, the USDA on Friday released the results of a study into how the disease spread this year in Iowa and Nebraska, information that will help officials tailor biosecurity and outbreak response plans.

Highly pathogenic avian influenza, called H5N2 or HPAI appeared in the U.S. late last year and has claimed as many as 48 million commercially raised birds, mostly turkeys and laying chickens.

The virus does not survive in hot weather, but epidemiologists expect it will begin to spread again in fall and want to be ready. In response to questions from House Ag Committee members, Vilsack said USDA is preparing to respond if avian flu begins to spread in fall, plans that include updated biosecurity, depopulation and disposal protocols, as well as indemnification and repopulation.

“We are planning for a circumstance where we're simultaneously having to deal with 500 outbreaks," Vilsack told the committee. "We think that’s sort of a worst case scenario situation."

MAKING VACCINE

One option to fight the spread of HPAI is a new vaccine; USDA has developed a seed strain that is 100% effective on chickens and being tested on turkeys.

If the vaccine works on turkeys, Vilsack said, a company with a license agreement will begin to manufacture the vaccine and stockpile the vaccine.

There remains some questions about how trading partners will react to a vaccine, since flocks then would carry an ineffective form of the virus and couldn’t show with certainty that they weren’t exposed to the live virus. It will be up to trading partners to not "hold it against us for using it," Vilsack said.

He expects to have deeper discussions regarding the impacts of avian flu on trade during next week's Iowa meeting. There, he said he plans to talk about countries' bans, urging them to ban poultry regionally, not products from the entire country, in the event of another large AI outbreak.

HOW IT SPREADS

To get a better idea how the virus spread across the Midwest in spring, USDA studied 26 farms where flocks caught the disease and 33 farms nearby that did not get hit.

Researchers found proximity is a huge risk factor. Half of the farms with a positive case were within a few kilometers of a farm with a case, while only 9% of the control farms was close to another farm with a positive case.

Corn on a nearby field was a risk factor. Farms that were less than 100 yards from a public gravel or dirt road had lower risk.

Inside the barn, disinfection in addition to cleaning brought a lower risk of infection when hard surface entry pads were present. Having a shower for employees to use was associated with a higher risk of barn infection; however, when case and control barns were compared with requirements for employees to shower, the significance of the association declined.

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