The highly pathogenic form of H5N2 avian flu was confirmed today on four more commercial turkey farms in Minnesota—three in previously unaffected counties—affecting 189,000 birds, while an H5 strain was detected in a North Dakota turkey flock.
The virus has now infected turkeys on 13 Minnesota farms in a little over a month. Minnesota officials also announced today that a farm housing more than 300,000 turkeys whose outbreak was announced 2 days ago will need to cull all the birds on its premises.
Almost 900,000 Minnesota birds now affected
The new outbreaks have affected 48,000 turkeys in Cottonwood County, 66,000 in Lyon County, 30,000 in Watonwan County, and 45,000 in Stearns County, the US Department of Agriculture (USDA) said today in an update.
The 189,000 newly affected turkeys bring to 872,000 the number of affected birds on Minnesota commercial farms since early March, the Minnesota Board of Animal Health (MBAH) said in an update today.
The outbreak in Stearns County is its fourth in recent weeks, while the other three counties are experiencing their first outbreaks. The newly affected counties are in the southwest corner of the state, south of the Minnesota River, while Stearns County is in central Minnesota. Cottonwood and Watonwan are neighboring counties, while Cottonwood abuts Nobles County, which reported an outbreak on Apr 2.
All nine affected Minnesota counties are in the Mississippi flyway followed by migrating wild birds.
As with previous outbreaks, samples from the four newly affected flocks were tested at the University of Minnesota Veterinary Diagnostic Laboratory and the USDA's Animal and Plant Health Inspection Service (APHIS) national lab in Ames, Iowa, after elevated levels of bird deaths were noted.
All birds on the affected farms will be euthanized to prevent disease spread, officials noted.
The MBAH also said today that all turkeys on a Meeker County farm of 310,000 birds that was confirmed to be H5N2 infected on Apr 8 will need to be euthanized. Beth Thompson, DVM, JD, MBAH assistant director, told CIDRAP News on Apr 8 that there was a chance that some of the turkeys might be spared, but that did not turn out to be the case.
Minnesota is the nation's largest turkey producer, at 46 million birds per year, according to the Minnesota Turkey Growers Association (MTGA). Newly affected Lyon County is the fourth-leading turkey-producing county in Minnesota, according to the MTGA. Kandiyohi, which has had two H5N2 outbreaks, leads the state, followed by Stearns County.
H5 in North Dakota
Meanwhile, a state veterinary lab in North Dakota confirmed H5 avian flu in a commercial turkey flock in Dickey County in the southeastern part of the state on the border with South Dakota, the Associated Press (AP) reported yesterday.
North Dakota State University's Veterinary Diagnostic Lab confirmed that samples from the flock of 40,000 turkeys tested positive for H5 after the flock owner reported elevated death rates. State officials are awaiting results from the APHIS lab in Ames for the exact strain, which could be H5N2.
South Dakota has had two H5N2 outbreaks in a week, the most recent reported yesterday. They were in separate counties in the east-central part of the state, more than 100 miles from the North Dakota outbreak.
In addition to the Minnesota and South Dakota outbreaks, Missouri has had two H5N2 outbreaks in recent weeks and Arkansas one. The virus was also confirmed in a backyard poultry flock in Kansas last month, and earlier in the winter it cropped up in several western states.
The APHIS said in today's update that the USDA's avian flu response plans call for federal and state officials to follow five response steps: (1) quarantining poultry and equipment, (2) eradicating affected flocks, (3) monitoring wild and domestic birds in the outbreak region, (4) disinfecting affected farms, and (5) testing the farm to ensure it is free of avian flu viruses.
The Centers for Disease Control and Prevention calls the risk of H5N2 to humans low. Human cases have yet to be detected.
H5N1 in Vietnam
In related news, the highly pathogenic H5N1 avian flu strain was confirmed in a village poultry flock in Vietnam, according a report posted yesterday by the World Organization for Animal Health (OIE).
The affected flock, in the southern Can Tho province, consisted of 900 birds. Of those, 650 contracted the disease and 399 died. The remainder of the flock will be culled to curb the outbreak, the report said.
Vietnam has reported seven previous such outbreaks to the OIE since December.
See also:
Apr 10 USDA APHIS update
Apr 10 MBAH updated summary of outbreaks
MBAH outbreak page
Apr 9 AP story
Apr 9 OIE report
Apr 8 CIDRAP News story "Ninth Minnesota turkey farm struck by H5N2"
Apr 9 CIDRAP News story "H5N2 hits second South Dakota turkey farm"
