The official count of outbreaks of highly pathogenic avian influenza has increased to 135 following the confirmation of two new cases by the USDA's Animal and Plant Health Inspection Service (APHIS) on 6 May:

• Iowa, O'Brian county - backyard ducks (number pending)
• Minnesota, Kandiyohi county - 65,000 commercial turkeys.

In both of 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.

Two new outbreaks suspected in Iowa

The Iowa Department of Agriculture and Land Stewardship reported on 7 May that it is responding to two probable cases of highly pathogenic avian influenza (HPAI) in commercial poultry farms:

• Osceola county 3 - 100,000 layer pullets
• Cherokee county 4 - turkey farm (number pending)

Both 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.

With avian influenza continuing to wreck havoc in northwest Iowa, poultry producers may get some help disposing of more than 20 million chickens, turkeys and ducks infected by the deadly virus, officials told Des Moines Register.

The Iowa Department of Natural Resources has issued three temporary permits to a Massachusetts company that would allow it to set up large portable incinerators in Sioux, Kossuth and Cherokee counties to help in the disposal of several million infected birds that have died from the disease or have been destroyed to prevent its spread.

Two new outbreaks suspected in Minnesota

On 7 May, the Minnesota Board of Animal Health announced there were two new presumptive virus-positive flocks:

• Kandiyohi county 32 - turkeys (number of birds pending)
• Swift county 6 - turkeys (number pending)

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 7 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).

New study shows bird flu virus can be spread in the wind

Researchers, led by Marcel Jonges at the Dutch Centre for Infectious Disease Control, have modelled the spread of avian flu viruses in the wind from infected poultry farms.

Jonges M,, J. van Leuken, I. Wouters, G. Koch, A. Meijer and M. Koopmans. 2015. Wind-mediated spread of low-pathogenic avian influenza virus into the environment during outbreaks at commercial poultry farms. Plos One. Published: May 6, 2015DOI: 10.1371/journal.pone.0125401

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 135.
• 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 (101); 19 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 25.78 million. This figure includes more than 20.32 million commercial chickens and 5.38 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.