On 7 May, the Animal and Plant Health Inspection Service (APHIS) of USDA confirmed seven new outbreaks of highly pathogenic avian influenza in poultry, all in Iowa:

• Iowa, Wright county - 2,800,000 commercial chickens
• Iowa, Sioux county - commercial chickens (number pending)
• Iowa, Sioux county - 80,998 commercial turkeys
• Iowa, Sioux county - 1,000,000 commercial chickens
• Iowa, Osceola county - 100,000 commercial chickens
• Iowa, Buena Vista county - 45,000 commercial turkeys
• Iowa, Buena Vista county - 100,000 commercial turkeys.

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

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

Seven new outbreaks suspected in Iowa

On 8 May, the Iowa Department of Agriculture and Land Stewardship reported it was responding to seven probable cases of highly pathogenic avian influenza (HPAI) in commercial poultry farms.

These seven new cases would join 37 cases of the disease in Iowa that were previously announced, making a total of 44 outbreaks.

• Wright county 2 - 2.9 million commercial laying hens
• Wright county 3 - 1.1 million commercial laying hens
• Buena Vista county 11 - commercial turkeys (number of birds pending)
• Buena Vista county 12 - 42,000 commercial turkeys
• Cherokee county 5 - commercial turkeys (number pending)
• Sac county 3 - commercial turkeys (number pending)
• Palo Alto - commercial turkeys (number pending).

All these farms experienced increased mortality and initial testing showed them positive for H5 avian influenza. Additional confirmatory testing is pending from the APHIS National Veterinary Services Laboratories (NVSL) in Ames.

State officials have quarantined the premises and once the presence of the disease is confirmed, all birds on the property will be humanely euthanised to prevent the spread of the disease.

Two new outbreaks suspected in Minnesota

The Minnesota Board of Animal Health announced on 8 May that there were no new presumptive virus-positive flocks.

A total of more than 5.59 million poultry on 84 farms in 21 counties have been affected in the state.

Wisconsin reports no new outbreaks

With no new outbreaks reported by the Wisconsin Department of Agriculture on 8 May, the state's total remains at 10 farms in four counties.

The total number of birds affected is over 1.76 million, comprising more than 1.11 million chickens and 652,000 turkeys (41,760 hatching eggs).

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 confirmed high-path avian flu outbreaks since December 2014 to 142.
• 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, an H5N2 variant of mixed Eurasian and American origin has been confirmed.
• The majority of outbreaks have been in commercial turkeys (104); 23 have been in commercial chickens, one in a mixed commercial flock and 14 in backyard flocks.
• The number of poultry affected by these outbreaks now exceeds 29.90 million. This figure includes more than 24.22 million commercial chickens and 5.60 million commercial turkeys as well as 7,173 backyard poultry.
• The disease has also affected five captive wild birds.