Q&A: How does the avian flu spread and what’s next for the current outbreak?

From skyrocketing prices to empty shelves in the egg section of grocery stores, the impact of the avian influenza outbreak is being felt far beyond the agricultural industry.

In Colorado alone, about 6.4 million chickens have died as a result of the virus in an outbreak that Dr. Kristy Pabilonia called the worst she’s seen in the U.S. in her two-decade career monitoring avian diseases.

Pabilonia is the director of Clinical Diagnostics for the Colorado State University Veterinary Health System of the College of Veterinary Medicine and Biomedical Sciences. She is an expert on diseases of poultry, and has worked closely with a number of international, state and federal agencies on foreign animal and zoonotic disease issues.

She spoke to SOURCE about the 2022 avian flu outbreak, the outlook going forward and why you should think twice before starting a flock of backyard chickens right now.

Even though the latest avian flu outbreak was first reported in the U.S. in early 2022, it’s reentered the headlines this year due to egg prices. What do you want people to know about the ongoing situation? 

The original lineage of this virus was first detected in 1996 in China, and it’s changed over time, much like how the COVID-19 virus has evolved.

The last U.S. outbreak of highly pathogenic avian influenza virus was in 2014-15, and in that case, it mostly infected commercial poultry but there were only a handful of infections in wild birds, which made it easier to stamp out the outbreak.

What’s different about the most recent outbreak is we’ve detected the virus in thousands of wild birds in the U.S., which makes it much more difficult to control, since these species migrate globally, making them really good at spreading the virus.

Most of the cases in commercial and backyard poultry are the results of wild bird introduction of the virus, making it very difficult for producers to prevent introduction of the virus into their flocks. It’s also a very deadly virus, and agricultural officials are working to depopulate flocks where the virus is detected and dispose of the bodies properly.

Colorado has lost almost its entire egg-laying population during this outbreak, which is why egg prices are as high as they are and there’s a lower supply.

The other thing to note is that because the virus is in wild birds it’s now not possible to fully stamp the virus out of the U.S, so we’re focusing efforts on preventing transmission from wild birds to domestic poultry.

How exactly do wild birds spread the virus to domesticated ones? 

Avian influenza virus spreads similarly to the flu in humans by transmitting bird to bird. Birds can shed the virus in their respiratory and fecal secretions. People can also play a role in spreading the virus, such as  foot traffic contaminated by bird droppings or contaminated clothing and equipment.

The reservoir for avian influenza viruses are waterfowl and shorebird populations. It’s a smart virus, because it has picked a reservoir species that commingle with each other and migrate all over the world.

It’s inherently a very contagious virus, and when you get one sick bird in a commercial operation, it spreads very quickly.

But again: We’re not just seeing this virus in commercial operations. We’re seeing it in backyard flocks too.

There’s been chatter on social media from people who are considering raising backyard chickens to avoid buying the expensive eggs in stores. You’re saying that might not be the best solution? 

I don’t recommend getting backyard flocks at this time due to the risk of highly pathogenic avian influenza. I support backyard chickens, but now’s not the best time to start your flock. It’s very hard to keep wild birds out of your backyard, and I don’t recommend raising chickens inside due to the potential spread of pathogens from birds to humans.

If you already have backyard chickens, I recommend protecting them from wild birds getting into their areas, such as keeping them cooped up as much as possible and netting over their outside spaces. We’re even detecting avian flu cases in small birds like crows or ravens, which are easily able to get into small areas.

What’s the risk of humans getting sick from the avian flu? 

The Centers for Disease Control and Prevention is only listing one human case of the avian flu in the U.S. during this outbreak, and there have been scattered cases in other countries. So far, it’s been encouraging, but we don’t want the virus to evolve and be able to spillover to humans more easily.

Avian flu testing lab

A laboratory technician processes samples at Colorado State University’s Veterinary Diagnostic Laboratory (Photo: John Eisele, CSU)

What are scientists like you doing to monitor the avian flu outbreak? 

The CSU Veterinary Diagnostic Laboratory in Fort Collins is a Tier I lab with the USDA’s National Animal Health Laboratory  Network (NAHLN), and is currently testing wild  and domestic birds for the avian flu. We get samples from all over the U.S., and have run more than 10,000 tests since the outbreak began.  The VDL also coordinates the Colorado Avian Health Program, which provides avian health services to commercial producers and backyard flock owners throughout Colorado.  This program has been very involved educating producers and owners, collecting samples and aiding in the response to positive flocks.

We’ve worked with many state and federal agencies, including the Colorado Department of Agriculture, Colorado Parks and Wildlife and the U.S. Department of Agriculture, to monitor the presence of the virus in our wildlife and domestic bird populations, as well as the monitoring for the virus in other captive populations such as zoo birds.

This Colorado Avian Health Program has a hotline number for questions related to avian influenza or other general poultry disease: (970) 297-4008. For more information, go to col.st/OmEjp.