Bird flu shows U.S. not ready for next big outbreak
The fight to contain avian influenza, which has forced the destruction of nearly 45 million birds in 15 states, is raising red flags about America’s biosecurity and its ability to fight even more virulent diseases in the future.
“In the Midwest, we’ve always said our biosecurity efforts were sufficient to deal with this … but we’ve never really been challenged,” said Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota.
“Obviously, the biosecurity systems we have are not adequate.”
Getting answers is important, not only to protect animals, but potentially humans as well.
Although there is evidence that the bird flu’s rampage may be winding down, experts still aren’t certain how the disease is being spread. And if fall waterfowl migrations and cooler temperatures usher the virus’ return, Iowa, Minnesota and other states could be vulnerable again — with potentially more states stricken as well.
“There is that possibility it could mutate and be a somewhat different virus when it comes back,” said Jim Roth, director of the Center for Food Security and Public Health at Iowa State University. “Those things are unknown.”
Avian flu already ranks as the worst outbreak in the nation’s history, based on the number of birds infected. It’s pummeling Iowa, the nation’s leading egg producer, and Minnesota, its top turkey producer.
Iowa’s losses have pushed close to 29 million chickens, turkeys and ducks destroyed by the virus, with nearly 70 outbreaks. And Minnesota has seen an estimated 8.3 million birds destroyed, mostly turkeys, at more than 100 farms.
In all, nearly 45 million birds at about 200 operations in 15 states have been killed or destroyed.
The economic impact on Iowa and Minnesota alone is an estimated $1 billion, The Associated Press has reported.
Experts worry this virus — or an even more virulent one — could hit the East Coast, which has billions of chicken broilers in states such as Georgia and Arkansas and millions of turkeys in North Carolina.
John Glisson, who oversees research for the U.S. Poultry & Egg Association, said avian flu’s return might not be as bad as feared.
The migratory waterfowl that introduced the virus in the Pacific Northwest last fall didn’t bring the disease back again this spring. He’s hoping the birds carrying the virus will develop an immunity.
“We thought for sure we’d have cases in California, Oregon and Washington and British Colombia, but we didn’t,” he said, noting that it moved instead to the Mississippi flyway, which includes Iowa. Experts believe one way avian influenza spreads is when migrating birds such as ducks and geese leave their droppings on farms.
Its unpredictability means the U.S. must be ready for anything.
“We know all these potential scenarios exist,” he said. “But not knowing which one will happen, we try to prepare for them all.”
The big unknowns
The nation faces “two zillion-dollar questions,” said Osterholm, also a University of Minnesota environmental health professor.
“How and why is this happening, for which we don’t have answers yet. … and what do we do about it to prevent it from happening in the future?”
Without answers to the first question, “how and why,” it’s difficult to address the second one.
“We have to answer the first one. Failure is not an option here,” Osterholm said. “That’s what we’re working on.”
Glisson said a team of epidemiologists is analyzing dozens of infected farms — from massive egg-laying and turkey operations to backyard flocks — like crime scene investigators to determine how the birds were infected.
It’s a massive undertaking that requires talking with hundreds of people.
Glisson, Osterholm and others anticipate the answers will show the virus was transmitted several ways — droppings from infected ducks and geese, transported on people’s shoes and clothing, as well as on equipment and vehicles.
The virus also could have come in on feed or water. Even flies and rodents could be carrying the disease.
Scientists also suspect the disease is traveling through the air, attached to dust or feathers. It also could be “aerosolized,” being carried on the wind.
‘A big mystery’
The U.S. Department of Agriculture is getting a partial idea of how the virus is spreading — or not, said T.J. Myers, the USDA’s associate deputy administrator of veterinary services. It has found, for example, workers at different facilities — one infected, another not — living in the same home.
It has found that facilities closer to water are infected. And it has found that wind sometimes plays a role, with facilities “downwind getting infected.”
But Iowa data are still being analyzed, he said. “We haven’t cracked the mystery by any means,” he said, adding that data so far is preliminary.
If the virus is carried on the wind, it could dramatically change the way officials respond, Osterholm said.
“Biosecurity was always set up in a concentric circles, like an explosive device — you go out 1 mile, 4 miles or 5 miles — quarantining farms in that area,” he said.
“But if it’s moving with the air, such as wind, it’s going to be a plume phenomenon. It’s like smoke. If you’re in that plume, you might be miles downstream and be impacted. But if you’re 500 yards off the plume, even if you’re adjacent to that farm, you may not be at risk.”
Glisson said one Minnesota outbreak — occurring on a hot, dry, windy day — made him consider wind transmission.
“I suspect that this might have happened, but I’ll be surprised if that’s a major part of the spread,” he said.
Osterholm also suggests that destroying birds in an infected facility could itself create “a virus cloud, because of the increased activity and movement.”
“We know the virus is getting into the barns somehow, so there’s some kind of breach in biosecurity,” said Tim Boyer, an epidemiologist at the National Center for Food Protection and Defense at the University of Minnesota-Twin Cities.
“In the end, it’s a big mystery to everybody involved,” Boyer said. “There will be a lot of work over the coming months to pinpoint how it’s getting into these barns.”
The Iowa Department of Health has been closely watching about 200 workers to determine if any becomes ill by the virus, said Patricia Quinlisk, the agency’s medical director.
Some workers, early in the outbreak, chose to take an anti-viral as a precaution because they worked for a while without masks.
No one has become ill, and Quinlisk doesn’t expect anyone will.
No human cases have been found of avian influenza, and health officials have said the strain poses a low risk to the public.
There also is no food safety risk for consumers.
But Osterholm worries a new avian influenza strain could emerge in the years ahead that could make humans sick.
It’s a concern that gripped millions in 2004, when the H5N1 virus in Asia that killed tens of millions of poultry also sickened several hundred people — about half of whom died.
The feared pandemic never materialized, though.
Concerns emerged again in 2013, when the H7N9 low pathogen strain infected primarily China, killing about 200 people.
Pathogen mixing bowl
Osterholm said Iowa and other states have “created these mixing bowls in our communities” for a more aggressive virus to develop.
“Today, pigs basically are the ideal mixing vessels for bird influenza viruses and human influenza viruses,” Osterholm said. “Their lung cells actually have receptors for both types of viruses, so when bird viruses are floating around and human viruses are floating around, they can co-infect a pig’s lungs at the same time.”
“What we don’t know is if we keep passing these viruses through potential reservoirs of, say pigs, will we suddenly see a human virus spin out. I worry about that a lot.”
Quinlisk doubts it would happen.
“We do know that in rare circumstances an avian virus can get in the same animal as a human virus,” she said. “And if those two viruses are replicating in the exact same cell, they can share some DNA.
“Most of the time when they do that, you end up with a virus that’s not viable. It dies. Every once in a while, that recombination can produce a virus that could cause human illness. But it basically causes human flu.”
It won’t suddenly morph into some deadly virus, like turning into Ebola, Quinlisk said. “Most humans have been exposed to flus and have immunity to them.”
And vaccines are effective against influenza, she said.
Glisson said the current virus would have to “really change” to make people sick. “We’d have to see a dramatic recombination event in order for it to become infectious for humans.
“All of these things are possible, but they’re possible all the time,” he said.
Preparing for worse
But Osterholm believes that U.S. officials need to imagine a pandemic outbreak to be able to respond to the possibility — no matter how remote.
“We’ve never seen anything like this,” he said. “We’ll continue to see this evolution of high-pathogen avian influenza viruses circulate around the world.
“This kind of discussion is absolutely critical. We’ll only get out of the situation by solving it; the only way we’re going to solve it is to be intellectually and scientifically honest about what we’re doing, what the challenges are.
“My goal isn’t to scare people out of their wits, but to scare them into their wits.”
Animals, food, national security
Jim Roth, director of the Center for Food Security and Public Health at Iowa State University, is concerned that the U.S. Department of Agriculture lacks enough staff to respond to large outbreaks such as this spring’s avian influenza.
The USDA has tapped retired workers and a corps of veterinarians, he said, to help respond to the outbreak. It also contracts with companies to help with euthanizing birds and cleaning and disinfecting facilities.
The federal agency has earmarked $413 million to help pay producers for their losses and cover cleanup costs.
T.J. Myers, the USDA’s associate deputy administrator of veterinary services, said the agency — and states — have planned and prepared for an avian influenza outbreak. But the magnitude of this outbreak was difficult to anticipate. “We’re now up to about 200 cases, and all that’s been compressed into about a six-week period,” he said.
Getting the “sheer number of people required … has been a bit of a scramble,” he said. “It’s required a huge amount of human capital, and that surprised everybody.”
The next couple of months will be critical to learning more about the virus and how to adjust biosecurity measures to prevent it from entering facilities. The USDA also plans to hold conferences in June and July on the outbreak to determine how it can better respond.
Another key discussion will be around bird flu vaccines, which could carry significant trade consequences. If using a vaccine destroys access to export markets, though, “the response could be more costly than the disease itself,” Myers said.
Roth said the nation also needs to worry about other animal diseases, such as foot-and-mouth disease and classical swine fever, called hog cholera. And the nation needs larger stockpiles of vaccines to respond to those diseases.
“We’ve been fortunate to keep out some very important diseases, but when a new disease comes in, our livestock has no immunity to it,” he said. “It can spread very rapidly.”
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