As avian flu spreads, health experts raise concern over the disposal of infected poultry birds

• The CDC’s principal deputy director and other health experts stressed the importance of wearing protective gear when culling poultry infected with the avian influenza virus.
• The CDC said a lack of protective equipment while culling chickens on a Colorado egg farm likely contributed to five cases of avian flu among workers, but so far no human or livestock cases have been directly linked to the culling of infected animals.
• Most of the culled birds are composted or buried, but some end up in landfills.

The spread of avian influenza on poultry and dairy farms has raised concerns among some health experts that the process of culling infected poultry could pose dangers to humans and livestock.

Recent cases of farms dumping carcasses in landfills or culling chickens to keep workers away from the virus show how the process of culling infected birds can further spread the disease, according to data seen by Reuters and interviews with officials and disease experts.

Extreme heat that made it difficult to wear protective gear during a carbon dioxide asphyxiation death at a Colorado egg farm likely contributed to five cases of avian flu among workers, the Centers for Disease Control and Prevention said this week, the largest human outbreak in the United States.

Can humans be tested for avian flu in the event of a potential outbreak? What you need to know

The incident highlights the need for systematic use of protective gear when culling sick animals, CDC principal deputy director Nirav Shah said in a conference call with reporters on Tuesday.

Dr. Michael Osterholm, an infectious disease expert at the University of Minnesota, said workers who slaughter chickens are at risk of inhaling the virus, and they have experienced mild symptoms such as conjunctivitis and respiratory problems.

“Depopulation efforts need to be explicitly focused on protecting these individuals,” he said.

So far, there have been no human or livestock cases directly linked to the culling of animals infected with avian influenza.

Colorado bird flu cases

Avian flu has spread to nearly every state in the U.S. over the past two and a half years, and nine cases have been reported among poultry and dairy workers since March, including a poultry worker in Colorado.

CDC officials said that while the risk to the general public remains low, if bird flu spreads more widely among farm animals, the possibility of human infections could increase.

About 95 million chickens, turkeys and other poultry have been slaughtered and destroyed since February 2022, according to U.S. Department of Agriculture data seen by Reuters, showing how they were killed and disposed of through late June.

Avian flu is deadly to birds, and governments require entire flocks to be culled if the virus gets onto a farm. While 2022 has been the deadliest year, data shows that the number of chickens culled so far in 2024 is roughly the same as in all of 2023.

Sick workers in Colorado, for example, were using mobile gas chamber carts to kill birds, Julie Gauthier, an official with the USDA’s Animal and Plant Health Inspection Service, said in a conference call Tuesday.

Gautier said the carts typically hold between 12 and 50 birds, which workers suffocate one at a time. A USDA spokesman said the department had investigated the farm’s use of the technique as part of its response to the outbreak.

More than 150 of the workers had come into contact with the infected poultry, 69 showed symptoms and were tested, five of whom tested positive, said Ann Marie Harper, public affairs director for the Colorado Department of Public Health and Environment.

Most of the chickens are killed by suffocation, either in portable chambers like those used in Colorado, by spraying the birds with firefighting foam or by cutting off ventilation to the chicken coop, according to USDA data.

A few are killed by firearms, cervical dislocation, or other means.

Disposal of animals infected with avian influenza

Most culled birds are composted in their coops or on farms, or buried, according to USDA data. Farmers compost the birds by covering them with wood chips and other materials, keeping the compost piles hot, and stirring them occasionally with farm equipment, a process that typically takes several weeks.

Federal and state officials are working with farmers to determine the best way to dispose of them, said John Clifford, a former USDA chief veterinarian who now advises the U.S. Poultry & Egg Export Council, an industry group.

Mya Walker, compliance supervisor for the Minnesota Animal Health Commission, said composting on-site is the safest way to avoid moving carcasses and spreading the virus.

In rare cases, carcasses are sent to landfills, but this disposal can meet federal and state regulations.

Michigan egg producer Herbrack dumped about 2 million chickens in a private landfill between April 15 and June 8, according to U.S. Department of Agriculture data and Michigan state waste disposal records reviewed by Reuters.

Herbrooks declined to comment.

According to USDA data, only 3% of all poultry will be sent to landfills after 2022, with the Hellbrook poultry outbreak accounting for about two-thirds of that.

Shortly after Harburg’s carcass was dumped, a dairy farm near one of the landfills tested positive for avian flu, alarming area farmers, but whole-genome sequencing showed that the discarded Harburg carcass wasn’t the source of the infection, said Adeline Hambly, Ottawa County health officer.

Click here to get the FOX News app

Wild birds helped spread the virus between poultry farms and to other species.

Minnesota veterinarian Brian Hofs said he doesn’t recommend disposing of dead poultry in landfills.

“That’s a restaurant for scavengers. It’s going to be a disaster,” he said.