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Keeping the bird flu ‘fox’ from the henhouse

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Seeing as May is Respect for Chickens Month, we thought we’d share this article about how to keep them safe from avian flu, which remains a very serious concern across much of the U.S. This story was originally published in our sister publication, Country Folks.

Cases of highly pathogenic avian influenza (more commonly known as HPAI or bird flu) have become more prevalent since 2022 after going undetected in the U.S. for several years. In the past 18 months, the disease has killed tens of millions of birds at poultry farms in 47 states and has killed or sickened several other types of domestic and wild animals.

Local farmers should be aware of the latest surveillance and monitoring efforts, which viral strains are being detected, which animal populations are being affected and response and prevention efforts to curb disease spread and prevent future outbreaks.

What Bird Flu Is

Bird flu is a virus normally found in wild birds including ducks, geese, swans and storks and domesticated birds like chickens and turkeys. The virus is easily transmissible among birds, but can rarely cause infections among people.

Dr. David Swayne, poultry veterinarian and former director of the USDA Agricultural Research Service’s Southeast Poultry Laboratory, said most of the time, for human infection to occur, “it would have to involve actually handling the poultry.”

Swayne emphasized that not all bird flu viruses are the same and described two different categories of which farmers should be aware.

“The first category is what we call low pathogenicity viruses. And these are viruses that generally grow or replicate in local areas, such as in the respiratory tract or in the digestive tract. And usually when poultry are infected by these viruses, they show a mild respiratory disease with coughing or sneezing. But also in chicken hens or in turkey hens, they may have a drop in egg production by flock basis,” he said.

“The other category, as far as pathogenicity or disease production ability, are the viruses we categorize as high pathogenicity, and these are the real deadly viruses,” he continued. “This virus spreads throughout the entire body of the chicken or turkey, replicating in almost every type of cell in the body. In fact, if these birds are not vaccinated, they have a chance of having mortality up to close to 100% of the birds because they cannot survive it.”

How Wild Birds Affect the Bird Flu Problem

The world is currently experiencing the biggest outbreak in wildlife to date of avian influenza virus, with estimates of up to one billion cases of infected wild birds globally.

According to Dr. Nichola Hill, assistant professor of virology, disease ecology and global health at UMass, farmers need to understand how bird flu is moving through wild bird populations in order to better protect their flocks.

“I think a large, looming question for a lot of us is this: These latest outbreaks [of bird flu in wild bird populations] – do they represent a new era for bird flu? And the answer is yes,” she said.

Asked if wild birds contribute to spread differently, Hill answered with a resounding yes. “The current stream of highly pathogenic H5N1 is particularly well-adapted to spread amongst waterfowl, ducks, geese and swans. It kills some, but it leaves some alive, and those infected birds can actually spread the virus geographically over sometimes quite really large distances,” she explained.

“Waterfowl, and specifically ducks, are this great host, ecologically speaking, for the virus because they both swim and fly. So there are multiple modes of spread for the virus this way. Outside of ducks, most species [affected] are waterfowl, those that are taxonomically related to ducks. Most bird species have quite high fatality rates compared to ducks.

“This is an indicator that the virus is actually quite well-adapted or adapting in real time to these species of ducks and waterfowl,” Hill continued. “We have now over 150 of the approximately 1,000 bird species in the U.S. that have been infected with highly pathogenic H5N1.”

Swayne advised farmers to keep their birds indoors for a period of time while the risk of infection from migratory waterfowl is high. When they migrate away from the farm, then farmers can take their birds back outside.

Keeping the bird flu ‘fox’ from the henhouse
Dr. Yuko Sato, a poultry veterinarian and associate professor of veterinary medicine at Iowa State, offered advice on how to deal with bird flu. Photo courtesy of Yuko Sato

What Farmers Can Do

What steps can small or local farmers who are largely isolated and have limited resources do to mitigate their risk of an outbreak on their ag operations?

Dr. Yuko Sato, a poultry veterinarian and associate professor of veterinary medicine at Iowa State University, offered her advice. “Be informed! If you’re a small producer, make sure you have some sort of credible resources that you can reach out to. Ask what sort of outbreaks or infections have been around in your area. This can kind of give you a little bit of an alert,” Sato said.

“Have sensible biosecurity practices. You don’t have to be in a fortress protecting [your flock] from everything that potentially could be harmful, but keep track of things like whether or not you’ve recently been to a poultry show,” she added. “Ask yourself – Am I showering and changing my clothes before I handle my poultry? … Let’s say there’s a pond or some sort of water source that ducks and geese can hang out in. Are those close to my poultry?

“Little things here and there that make sense, that’s practical, are probably the best ways to keep these producers from getting birds infected.”

Farmers also need to be aware of the potential for virus spillover from wild birds to wild mammals. Species that eat or swim with birds are really at highest risk in the wild. This includes osprey, bald eagles, red-tailed hawks, foxes and coyotes. Red foxes actually account for half of these mammalian infections, most likely due to foxes predating on ducks. A fox in the henhouse is bad enough, but an infected fox is even worse.

Swayne added that USDA’s Animal and Plant Health Inspection Service has a program called Defend the Flock. He recommended farmers visit the program’s website to get basic information about how, as small flock owners, they can provide biosecurity to reduce the risk to their birds.

For more information visit aphis.usda.gov/aphis/ourfocus/animalhealth/animal-disease-information/avian/defend-the-flock-program.

The World Organisation for Animal Health also provides a global perspective on the issue at woah.org/en/disease/avian-influenza.

by Enrico Villamaino

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