JASPER, Ind. — In addition to nearly 259,000 commercial turkeys destroyed on 10 farms in Dubois County last week following testing for highly pathogenic avian influenza (HPAI), 156,178 commercial chicken layers testing negative were nonetheless also killed for being too close to one of the infected turkey flocks.

The USDA’s Animal Plant Health and Inspection Service (APHIS) and National Services Laboratory began a second round of testing late last week on poultry testing negative on the first culling for HPAI virus, within in the 20-kilometer (nearly 12.5 miles) zones surrounding each of the 10 farms. The State Board of Animal Health (BOAH) imposed a 10-km surveillance zone beyond the 10-km control zone that the USDA mandates to restrict the movement of poultry products.

Immediately after HPAI H7N8 was identified as the culprit behind hundreds of deaths in a 62,109-turkey flock earlier this month, Indiana State Veterinarian Dr. Bret Marsh told reporters, “We’re prepared to go to the extent necessary to preserve and protect this sector.”

Since then, more than 500 state, local and federal responders have moved in or been dedicated locally in Dubois County to halt the spread of the HPAI virus. Of the 414,503 birds euthanized as of Jan. 21, the HPAI virus was found only among the original 62,109-turkey flock; eight of the other nine turkey flocks tested positive for the low pathogenic virus and one was suspected of H7N8.

“We do definitely have animal disease and natural (and) agriculture issues” in the county response plan, though nothing specific to avian influenza, Dubois County Emergency Management Director Tamara Humbert said. The plan accounts for these types of outbreaks,

BOAH is the lead agency. So far she is “very impressed” with BOAH’s rapid response and the USDA’s cooperation.

The compliment was reciprocated by BOAH Public Information Director Denise Derrer; besides the response of local livestock producers and agencies and first responders, she said the Dubois County Health Department is working with local hospitals to monitor anyone who had direct contact with the euthanized birds, for up to 10 days after.

The U.S. Centers for Disease Control and Prevention states the HPAI risk to humans is a low possibility for those in direct contact with infected birds.

Workers had visited almost 2,000 residences in the 20-km monitor zones as of Friday and tested 96 backyard poultry flocks for influenza viruses, Derrer said. All tested negative but will be retested 14 days later. And the testing will continue for some weeks on all flocks in the control zone because the viruses can survive in some low temperatures. BOAH is also working with the Indiana Department of Natural Resources and the U.S. Fish & Wildlife Service to test wild birds.

Once a farm flock is identified positive for the virus, the USDA’s goal is to depopulate it within 24 hours; Derrer reported it actually took six days because of weather and other issues that hampered the work. While the uninfected layer hens were disposed of in a landfill, the turkey carcasses are being composted in the buildings where they were killed.

BOAH did not report any destruction of eggs from the layers; Derrer did not know what happened to the eggs, but said since the chickens were uninfected, their eggs might have been delivered to the farmer’s buyer(s) as normal.

The compost piles must be monitored for 29 days, she said, turned and managed daily according to a “recipe” experts are on hand to help oversee. Workers monitor temperatures to keep them at high enough levels to kill the H7N8 virus. At the end of the cycle, the compost can safely be used for fertilizer, but the buildings have to be cleaned and disinfected to USDA standards that comply with international trade requirements.

There’s no one answer for how long a livestock producer must wait before they can repopulate their flock.

Derrer said the USDA must give approval to BOAH to lift the 10-km control zone and before doing that will require proof of each affected farm’s freedom from disease. The agency changed some of its requirements after last year’s massive national losses of almost 50 million birds to HPAI.

“We’ve got to be flexible and be willing to adapt,” she said. “If (USDA) didn’t change, they wouldn’t necessarily be doing (response) the right way.”

Of course, this is if further tests are all negative.

“If we find a new highly pathogenic positive, it just sets us back to day one,” Derrer pointed out.

In late 2015, the USDA awarded contracts to Iowa-based Harrisvaccines Inc. and the French firm Ceva Corp. to manufacture and stockpile tens of millions of vaccine doses against H5 strains of HPAI since that was what caused the death of poultry last year in the United States. These are not for sale or use except under order from the USDA.

Since then, Merck & Co. Inc. has bought Harrisvaccines – but it still has the USDA contract as a subsidiary of Merck, said Joel Harris, associate director of marketing.

Though the vaccines are not for the H7 strain in Dubois County, he said Harrisvaccines was actually working last spring on one for H7N9 strains, which are a problem in other parts of the world.

He explained if the USDA does decide to order new vaccines for a non-H5 strain, the company would not need a live virus to begin development, just the genetic sequence data. Its proprietary SirraVax technology means researchers can develop a tailored vaccine in 4-8 weeks.

“Our technology allows us to swap out different strains into our production platform,” Harris said.

Dr. T.J. Myers, associate deputy administrator of veterinary services with USDA’s Animal Plant and Health Inspection Service, said on Jan. 15 the agency is not looking at releasing vaccines at this time even with the Dubois County situation.