Minnesota declares H5N2 emergency as spread continues

Minnesota Gov. Mark Dayton today declared an emergency over the widespread H5N2 avian influenza invasion of poultry farms, as the state's first outbreaks in chickens and backyard poultry were reported and Wisconsin and Iowa each announced a new turkey outbreak.

By declaring a state of emergency, Dayton activated an emergency operations plan to support the state's response to the crisis, the Minneapolis Star Tribune reported. The state has logged 46 outbreaks in 16 counties, with more than 2.63 million birds either killed by the virus or destroyed to stop its spread, according to the Minnesota Board of Animal Health (MBAH).

Dayton's action also calls for National Guard troops to be used as needed, but it wasn't immediately clear whether any would be called up, the story said. On Apr 20, Wisconsin Gov. Scott Walker authorized the Wisconsin National Guard to help respond to H5N2, after the state veterinarian asked that a few Guard members be made available.

Large chicken farm hit

Minnesota's first H5N2 outbreak on a commercial chicken farm was reported today at J & A Farms, an egg operation about 20 miles west of Detroit Lakes in the northwest, the Star Tribune reported. In addition, the MBAH reported an outbreak in a mixed backyard flock of 150 poultry in Pipestone County, near the state's southwestern corner, the county's first outbreak.

Amon Baer, owner of the chicken farm near Detroit Lakes, told the newspaper he must destroy about 300,000 chickens after tests he ordered confirmed the presence of the virus. The story said the MBAH was aware of the test result and was in the process of confirming it. If confirmed, the outbreak will push the state's losses of turkeys and chickens close to 3 million.

Baer said that dealing with the outbreak will be very costly, since it includes cleaning and disinfecting facilities in addition to culling all the birds, according to the story. He said federal assistance will cover some of his losses but not nearly all of them.

Chickens are believed to be less susceptible than turkeys to H5N2, but a few chicken-farm outbreaks have been reported, including at least one each in Iowa and Wisconsin

The MBAH's list of 46 Minnesota outbreaks does yet not include the chicken-farm event. In addition, one of 15 reported outbreaks in Kandiyohi County is not yet included in the total, because the number of affected birds has not yet been confirmed, MBAH spokeswoman Bethany Hahn said today.

Another Wisconsin outbreak

Meanwhile, Wisconsin officials today reported the state's sixth H5N2 outbreak, on a farm with 90,000 turkeys. It's the second outbreak in Barron County in the northwestern part of the state.

In a statement, the Wisconsin Department of Agriculture, Trade and Consumer Protection said the property was quarantined and the surviving birds will be destroyed, as neighboring poultry owners are notified.

Wisconsin's first H5N2 outbreak surfaced in Jefferson County on Apr 13, and more outbreaks have occurred since then in Jefferson, Juneau, Chippewa, and Barron counties. In those counties, State Veterinarian Paul McGraw has banned movement of poultry to shows and swap meets, the statement noted.

More Iowa turkeys affected

Also, early this evening the Iowa Department of Agriculture (IDA) reported the state's third outbreak of highly pathogenic avian influenza (HPAI), involving a commercial turkey flock of 34,000 birds in Sac County in the western portion of the state.

The farm is within the 10-kilometer monitoring zone of an H5N2 outbreak in Buena Vista Country that was reported on Apr 14, Iowa's first H5N2 outbreak. This is Iowa's third outbreak of HPAI in poultry. The second, reported earlier this week, involved 3.8 million chickens in Osceola County, adjacent to Minnesota.

Preliminary tests indicate the outbreak was cause by an H5 strain, the IDA said in a news release, and samples have been sent to the US Department of Agriculture's National Veterinary Services Laboratories in Ames, Iowa, to confirm the exact strain.

Scientists see long-term threat

In other developments, an article in Emerging Infectious Diseases suggests that H5N2 and other descendants of the H5N8 avian flu virus that arose in Asia in 2014 may be a long-term threat to poultry and wildlife in the Northern Hemisphere.

The article, by three staff members of the US Geological Survey's National Wildlife Health Center in Madison, Wis., traces the emergence of H5N8 and its various progeny, including H5N2. It says the H5N8 virus apparently arose in China through reassortment of highly pathogenic H5N1 with various low-pathogenic viruses.

The H5N8 virus was first detected in early 2014 in poultry and wild birds in South Korea and subsequently surfaced in Russia's wild waterfowl in September, the article notes. Since then the virus and various reassortants have been found in poultry and wild birds in Europe, Taiwan, Japan, Canada (British Columbia), and the western and central United States.

Because wild waterfowl are natural hosts for avian flu viruses, and H5N8 seems to have little effect on them, "it seems probable that the virus was disseminated out of Russia into Europe, East Asia, and North America by migrating waterfowl during autumn 2014," the report says.

It goes on to state, "Persistence of the original HPAI H5N8 virus for >1 year, the creation of multiple reassortant viruses that have maintained high pathogenicity in poultry, and adaptation of the virus to migrating waterfowl all indicate that these viruses could persist and spread in Northern Hemisphere waterfowl populations for an extended period."

As the viruses persist, so does the threat of new genetic combinations that could arise in wild waterfowl and then spill over into poultry and other birds, the authors add. They ask, among other questions, whether these viruses might reassort with viruses from other species, such as swine, and whether such reassortant viruses might pose a risk to humans.

They also observe that H5N8 and related strains may be a threat to wild raptors, as suggested by the infections detected in gyrfalcons and a few other species in North America.

See also:

Apr 23 Star Tribune story

MBAH updates on H5N2

Apr 23 Wisconsin statement

Apr 23 IDA news release

Apr 22 Emerg Infect Dis report

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