The latest official report from the USDA Animal and Plant Health Inspection Service (APHIS) includes three new outbreaks of high-path bird flu confirmed on 29 April:

• Minnesota, Kandiyohi county - commercial turkeys (number of birds pending)
• Minnesota, Stearns county - 202,500 commercial chickens
• Iowa, Buena Vista county - 50,000 commercial turkeys.

In each of these outbreaks, the cause has been confirmed as the H5N2 subtype of highly pathogenic avian influenza virus of mixed Eurasian and American origin.

All these outbreaks are in the area of the Mississippi flyway for migrating birds.

Iowa reports nine outbreaks in two days; one in four layers lost to bird flu

Over the last two days, Iowa Department of Agriculture and Land Stewardship has reported nine confirmed or probable outbreaks of avian flu in poultry following increased mortality:

• Buena Vista 2 – Turkey farm with an estimated 50,000 birds.
• Buena Vista 3 – Turkey farm; number of birds at the site pending.
• Buena Vista 4 – Commercial laying operation with an estimated 63,000 birds.
• Kossuth County – Chicken breeder farm with an estimated 19,000 birds.
• Buena Vista 5 – Commercial laying operation with an estimated 5.5 million birds.
• Buena Vista 6 – Turkey farm; number of birds at the site pending.
• Buena Vista 7 – Turkey farm; number of birds at the site pending.
• Sioux 3 – Commercial laying operation with an estimated 84,000 birds.
• Clay – Commercial laying operation; number of birds at the site pending.

Iowa Agriculture Secretary, Bill Northey, told a press conference on 30 April that 17 farms in seven Iowa counties have been affected so far, compared with just three farms a week ago, reports CIDRAP.

Concerning the losses, Mr Northey said: "I believe we're somewhere north of 15 million layers right now. That would be about one-fourth of Iowa's layers. That's going to be five to six per cent of layers in the US. Once you start getting those kinds of number you can start having an impact."

He added that Iowa has lost some markets overseas, which keeps some of Iowa's production at home and could counterbalance to some degree any upward pressure on egg prices, "but we'll probably still see some impact".

No H5N2-infected migratory birds have been found in Iowa and noted that the virus's pathway into poultry barns remains a mystery, according to Mr Northey, who said some farms that are close to outbreak sites get hit with the virus but others do not.

He added: "There could be something that flew over and left something that somebody walks through and takes into the barn. We all wish we had all the answers as to exactly how this is moving."

Three new outbreaks in Minnesota; wild bird tests positive for virus

On 30 April, the Minnesota Board of Animal Health announced three presumptive positive flocks. The following Minnesota counties are affected:

• Otter Tail – 3rd detection (turkeys, flock size pending)
• Stearns – 13th (14,800 turkeys) and 14th detections (20,500 turkeys)

These brings the total number of farms affected to 70 in 19 counties.

A Cooper’s hawk from Yellow Medicine County is the first Minnesota wild bird to test positive for the highly pathogenic avian influenza (HPAI) virus that has infected poultry farms across Minnesota.

The Department of Natural Resources collected the hawk during the agency’s current HPAI surveillance of wild birds.

Lou Cornicelli, DNR wildlife research manager, said: “This bird tells us our surveillance is working, but it unfortunately doesn't provide many other clues about transmission of the virus.”

Overview of high-path avian flu outbreaks in US poultry

The following information is based on published USDA APHIS outbreak reports:

• The latest cases bring the total number of high-path avian flu outbreaks since December 2014 to 101.
• Outbreaks have occurred in poultry in 13 states.
• Three of the early outbreaks were caused by the H5N8 sub-type of the virus but in all those since mid-February 2015, the H5N2 variant has been confirmed.
• The majority of outbreaks have been in commercial turkeys (77); 11 have been in commercial chickens, one in a mixed commercial flock and 12 in backyard flocks.
• The number of poultry affected by these outbreaks now exceeds 15.76 million. This figure includes more than 11.4 million commercial chickens and 4.2 million commercial turkeys as well as 7,173 backyard poultry.
• The disease has also affected five captive wild birds.

Further Reading

You can visit the Avian Flu page by clicking here.