The bird-watchers

Avian influenza killed about 9 million birds in Minnesota this year, but U of M findings may help minimize the impact of future outbreaks

Carol Cardona knows that if you want to get answers to the most vexing problems in bird health, you can’t be afraid to get dirty. When a deadly avian influenza virus infected and killed millions of chickens and turkeys at more than 100 commercial farms in Minnesota this spring, Cardona, the University of Minnesota’s Pomeroy Chair in Avian Health, headed straight to the farms experiencing the problems.

She and other researchers col­lected water samples, swabbed dust from fan blades and mouse bait stations, and even gathered the litter that stuck to the cloth booties they wore into the barns. They then took these samples back to the lab and tested them to find clues about the way the virus was spreading. “For example, finding the virus on the fan blades might mean it came in through air vents, while finding it near bait stations might mean mice were involved,” she says.

In this case, the answer was more complicated: the cases were so spread out geographically that they seemed unrelated. In the end, Cardona and other researchers found no single smoking gun, though some speculate the disease was carried in the feces of wild waterfowl as they migrated north. 

What Cardona did know was that the virus’ miniscule “infectious dose” meant that any tiny weakness that the virus was able to exploit—heavy winds that blew dust and debris into the barns, for example—could lead to the infection of the birds, with a brutal 100 percent mortality rate.

But thanks to the work of indus­try and experts, the outbreak was ultimately brought under control, and a new case hasn’t been seen nationwide since June. Cardona and her colleagues have also learned key lessons that are helping them pre­pare for the fall season, when avian influenza picks up again. “For a long time, we have believed that the most important thing was to prevent infec­tion spreading from your neighbor,” she says. “That’s still important, but it’s also important to stop primary introductions of the disease—which we used to think were very rare.”

Cardona and her colleagues have worked with government and industry partners, including Minnesota’s Board of Animal Health and Department of Agriculture, to develop better systems to react quickly to prevent major outbreaks like this again.

Flock of white turkeys
Birds infected with avian influenza have a 100 percent mortality rate.

“The University of Minnesota isn’t a response agency, but we helped pull people together who needed to talk, made sure we had a good strategy, and supported good science,” she says. Cardona was also a go-to source for local media during the white-hot center of the crisis.

For Cardona, support through an endowed chair allows her to focus on doing her best work: pursuing both traditional fieldwork and unconven­tional ideas that may help prevent or control future outbreaks. “Because of this funding, I don’t have to do the work of seeking grants to support my own salary,” she says.

The support has also made it easier for Cardona to hire graduate researchers—she currently has two—to assist her with her own work and pursue new ideas. Cassie (Xi) Guo, a Ph.D. candidate, for example, has been working with turkey company veterinarians to study how weather patterns affect the spring introduc­tions of avian influenza in Minnesota turkeys. Guo, a recipient of the Pomeroy Legacy Scholarship, says she’s grateful for the funding. “It provides me the opportunity to do research without worrying about the financial burden,” she says.

While this spring’s avian influenza outbreak was stressful and finan­cially difficult for poultry producers, the good news is that there is no correlation between the strength of one season’s virus and the next—so for now, Thanksgiving lovers don’t need to worry about their traditional turkey feast being affected. “I can’t speculate for the whole country,” says Cardona, “but I would say that I’m definitely planning to have my turkey for Thanksgiving, and I’m planning to have a big one.”