Though he was managing a flock amid one of the biggest animal health emergencies in history, Nelson said he didn’t panic.
However, “you certainly were very much afraid.”
If even one bird on the farm came down with the virus, the whole flock — about 320,000 chickens at any one time — would have to be euthanized.
Nelson chained off the driveway to bar unauthorized visitors and stepped up farm cleanliness. At the same time, life had to go on.
“If it hit, it hit," he said. “You still had to run the business."
The virus surfaced in the Northwest in December 2014 and reappeared in the Midwest that spring. About 50 million birds were euthanized or killed by the virus, including about 9 million in Minnesota, which produces more turkeys than any other state.
No humans were infected, and the danger to the public from this strain of bird flu is considered by the Centers for Disease Control and Prevention to be low. Likewise, even in the unlikely incident an infected bird were slaughtered for meat, the odds of human infection through food is quite low, the CDC has said.
Instead, the cost of the avian influenza outbreak was measured in dollars (not to mention the suffering of birds). A University of Minnesota Extension study pegged the price tag at about $650 million in Minnesota. For Iowa, that total is $1.2 billion, including lost wages, jobs and taxes. Those figures do not include the value of the millions of birds euthanized in the outbreak — the government reimburses farmers for these birds (more on why later).
A year later, experts say they are better prepared for the next outbreak of what’s called “highly pathogenic” flu. Though they believe the disease arrived here on the wings of wild birds, experts don’t know for sure which birds spread the illness or how it was passed to the poultry.
What happened?
The word “influenza” comes from the Italian for “influence,” as the disease was once thought, like all manner of calamities, to be caused by the unfavorable alignment of the stars. We now know astrology does not cause influenza, but key details about last year’s epidemic remain unknown.
Still, the outbreak had a silver lining: It provided researchers with a plethora of data. Dozens of farms were hit, but many more were spared. Why?
A pair of studies in Iowa and Minnesota analyzed this data, looking for correlations between whether a farm was infected and, among other variables, its management practices, proximity to other farms and even the tilling of nearby crops.
The Minnesota study, which focused on turkeys, found the odds of being infected were, on average, 46 times greater in farms located near other farms, whether or not they were themselves infected. Perhaps the movement of workers from farm to farm played a role in spreading the illness, said Scott Wells, a University of Minnesota College of Veterinary Medicine professor who co-authored the study.
One intriguing correction found that, in the early part of the outbreak, tilling the field closest to a turkey barn was associated with an average 14 times greater chance of infection. Anyone who’s seen a field being tilled could come up with one hypothesis. Flocks of birds, especially gulls, often follow tractors to eat the insects and worms turned up by the till. Their feces, perhaps attached to a worker’s boots, could help transmit the virus.
One suggestion, then, would be to plant alfalfa, or other crops that don’t require early spring tilling, close to turkey farms.
In both the Iowa and Minnesota studies, rigorous management practices were correlated with farms that were spared.
In Minnesota, farms with high worker biosecurity were, on average, one-fourteenth as likely to be infected compared to farms that did not.
In Iowa, having a hard-surface barn entry pad that was cleaned and disinfected was found to be correlated with a lack of infection. (Click here to read the Iowa study.)
To be clear, neither study aimed to answer how the virus was introduced and spread. Instead, they raised more questions that can be tested in follow-up studies.
In addition, researchers have been analyzing the viruses’ genetic makeup to detect subtle variations and piece together a timeline.
Local area avoids worst
The brunt of the infection hit west-central Minnesota, with relatively few cases in Blue Earth County and surrounding counties. There was one case apiece in Blue Earth, Le Sueur, Nicollet and Watonwan counties, and five in Brown County.
The Nicollet County infection, announced May 4, 2015, struck a farm of 1.1 million chickens. That single event meant Nicollet County experienced the second-highest loss of chickens statewide after Renville County’s combined loss of 2 million chickens.
The farm Nelson manages, located about halfway between Nicollet and North Mankato, raises what are called pullets: hens aged between a day and about a year. After that, they are moved to egg-laying operations.
Though the virus was introduced by wild birds, Nelson said the industry soon decided it was being spread by people.
For example, each of their birds receive an injection of antibiotics, a task that takes a crew of 10 people almost a week. The farm has started providing these workers with its own clothes “so we know they’re clean,” Nelson said.
They also require visitors to step in a small basin filled with a disinfecting liquid (they switched from a powder).
Faster response next time
Even before last year’s outbreak, veterinarians had been looking for evidence of the virus, a practice called “surveillance.” This routine screening involved checking birds for antibodies, which the birds’ immune systems produce to fight illness.
But it didn’t detect this strain of the flu because it killed too quickly — within hours after showing symptoms, virtually 100 percent of infected birds die, before they have a chance to even make antibodies.
A more sophisticated test can ferret out the viruses’ genetic material, but the nearest lab that can perform so-called “polymerase chain reaction” or PCR testing is in St. Paul. That’s changing, though.
The Willmar-based Minnesota Poultry Testing Laboratory, a cooperative venture of the Board of Animal Health and University of Minnesota, is undergoing an expansion that will allow it to perform PCR testing, said Shauna Voss, a senior veterinarian with the board.
“With the ability to do this test in Willmar, we will be able to get official test results sooner and be able to act quicker,” she wrote in an email.
Overall, there’s no way to be sure what happened last year won’t happened again. The difference now, though is “we’re better prepared and have a stronger surveillance system,” she said.
And that’s important for more than just birds.
Steve Olson, executive director of the Minnesota Turkey Growers Association, said animal health and human health are ultimately linked. Viruses, if allowed to run unchecked through animal herds, can mutate and infect humans.
It is partly for that reason that farmers are paid when their poultry are euthanized; that way, there’s an incentive to report outbreaks.
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