Five more large chicken farms in northwestern Iowa, including egg-laying operations housing more than 9 million birds in all, have been hit by probable H5N2 avian influenza outbreaks, while the virus has invaded at least four more turkey flocks in Minnesota, according to reports today.
In addition, H5N2 has surfaced on another turkey farm in southern Ontario, while poultry workers associated with outbreaks in Minnesota are receiving an antiviral drug as a precaution.
Massive Iowa operations hit
The Iowa Department of Agriculture and Land Stewardship (IDA) today announced five more H5 avian flu outbreaks, affecting commercial farms in three counties in the northwestern corner of the state, two of which are reporting their first outbreaks.
The newly affected counties, O'Brien and Sioux, each reported two outbreaks. The fifth outbreak is in Osceola County, which earlier this month had an outbreak on a commercial chicken farm.
Four of the outbreaks are detailed in an IDA press release, and, at a media telebriefing today, Iowa Agriculture Secretary Bill Northey announced a fifth outbreak in Sioux County. Officials are awaiting final subtyping test results for all five events, but they believe the results will be positive for the highly pathogenic H5N2 strain responsible for outbreaks in Iowa and other Midwestern states.
The sites include a pullet facility raising layer chickens in Osceola County, two egg-laying operations in O'Brien County, a laying operation in Sioux County, and a turkey facility in Sioux County. In total, the five new Iowa outbreak affect 9.5 million layers, 250,000 pullets, and 80,000 turkeys.
Northey said that so far the outbreak impact has been limited, as Iowa's layer population is 60 million birds. However, he said if the outbreaks continue, they have the potential to cause major losses.
At today's telebriefing, T.J. Myers, VMD, associate deputy administrator of the US Department of Agriculture's (USDA's) Animal and Plant Health Inspection Service (APHIS) Veterinary Services, said the agency has indemnity funds to help farmers recover from the outbreaks, and since December has paid out $60 million.
Today's update from the USDA's APHIS included details on outbreaks that were first reported at the end of last week. It said the second outbreak in Wisconsin's Jefferson County, on a layer farm, has now affected 1,031,000 birds, up from 800,000 when state officials first announced the outbreak on Apr 22.
In Minnesota, the top turkey-producing county, Kandiyohi, had its 18th and 19th outbreaks, on farms holding 42,900 and 67,000 turkeys, the Minnesota Department of Public Safety (DPS) reported today.
In addition, Chippewa County in southwestern Minnesota reported its first outbreak, on a farm with 68,000 turkeys, and a fourth outbreak surfaced in Redwood County on a farm with 24,300 turkeys, the DPS said. Another flock in Redwood County will also be euthanized because it was identified as "a dangerous contact" of other sites.
The DPS also said the USDA confirmed Kandiyohi's 11th outbreak, which was apparently included in numbers mentioned earlier by the Minnesota Board of Animal Health (MBAH). The board now says 55 farms in 18 counties have been hit, with 3.11 million birds lost. That number does not include the birds on several farms where information is still being gathered.
APHIS's official tally of H5N2 outbreaks notes that about 7.7 million US poultry have been affected. That number does not include the newest Iowa outbreaks, which are not yet definitively categorized as H5N2 events.
Third Ontario farm affected
Elsewhere, a third H5N2 outbreak has been identified in southern Ontario's Oxford County, according to Canadian media and government reports.
A CBC News report yesterday said the Canadian Food Inspection Agency (CFIA) estimated that 8,000 turkeys on the latest affected farm will be euthanized to stop the virus.
The CFIA released little information about the outbreak, but noted in a timeline of events that it confirmed the virus as H5N2 on Apr 24. The agency said the farm has been under quarantine since Apr 19 and is part of the second avian flu control zone established because of the outbreaks.
The first outbreak was detected at a turkey farm near Woodstock, Ont., on Apr 5, and the second one was found on a chicken farm on Apr 18, according to the CFIA.
Workers get precautionary antiviral
In other developments, a Minnesota Department of Health (MDH) official said today that 73 people exposed to H5N2 during the state's outbreaks have agreed to take the antiviral oseltamivir (Tamiflu) as a precaution, although no human cases have been identified.
MDH spokesman Michael Schommer told CIDRAP News that the agency is currently monitoring 86 poultry workers for possible flu symptoms, including respiratory problems and eye infections. He said 74 people have completed 10 days of monitoring, with no infections detected. No human H5N2 cases have been reported anywhere to date.
"We've recommended Tamiflu for 93 people, and 73 people have agreed to take Tamiflu," Schommer said.
He also said 11 people in the program had cold-like symptoms, and resulting tests determined they did not have the virus.
No high-path findings in Minnesota wild birds
Although officials believe the H5N2 virus was brought to the Midwest by wild birds, a wide-ranging sampling program in Minnesota has failed to find any wild birds infected with highly pathogenic avian influenza (HPAI) so far, according to Michelle Carstensen, PhD, wildlife health program supervisor for the Minnesota Department of Natural Resources (DNR).
The DNR has been collecting fecal samples from waterfowl within 10 kilometers of outbreak sites in five counties, aiming to gather enough to provide 95% confidence of finding the virus if present in 1% of birds. For control sampling, the agency is also collecting similar numbers at wildlife management areas that are not close to any outbreaks.
Carstensen reported on Apr 25 that the DNR has submitted 2,314 fecal samples for testing, including 1,740 from waterfowl in areas near infected farms and 574 from control sites. Test results on 915 of these revealed no HPAI viruses and just seven low-pathogenic viruses, she said.
The DNR also has submitted samples from 21 wild birds that were found dead or sick, including raptors, wild turkeys, and other species, she reported. Eight results have come back, and all were negative for HPAI.
Testing of samples from hunter-killed wild turkeys is just beginning, Carstensen said. A first batch of 18 samples was submitted for testing Apr 23, and more will be submitted this week.
Preliminary testing is done by the USDA's National Wildlife Disease Laboratory in Ft. Collins, Colo., according to the DNR's surveillance plan. Any samples that are positive for H5 or H7 viruses then go to the USDA's National Veterinary Services Laboratories in Ames, Iowa, for confirmation and further typing.
Apr 27 IDA press release
USDA list of outbreaks
Apr 27 Minnesota DPS statement
MBAH list of Minnesota outbreaks
CFIA timeline of events in Canada