# 2015 United States H5N2 outbreak

In 2015, an outbreak of avian influenza subtype H5N2 was identified in a series of chicken and turkey farming operations in the Midwestern United States. By May 30, more than 43 million birds in 15 states had been destroyed as a result of the outbreak, including nearly 30 million in Iowa alone, the nation's largest egg producer. In the Midwestern U.S., the average price of eggs had increased 120% between April 22 and May 30. The effects however were seen nationwide, with prices in California up 71% in the same timeframe.
The virus was first identified in Minnesota in early March. Prior to April 20, it affected commercial turkey farms almost exclusively, in the states of Arkansas, Iowa, Missouri, North Dakota, South Dakota, Wisconsin, and at 28 farms in Minnesota, where the virus was initially identified. Migratory waterfowl are assumed to have brought the disease to the Midwest, but how it made its way into poultry barns is undetermined.

## Spread to hen farms

On Monday, April 20, the U.S. Department of Agriculture announced that 5.3 million egg-producing hens at a northwest Iowa farm must be destroyed after the virus was confirmed. The number at this operation alone comprised a little over 1% of egg-laying hens in the United States.
As of May 27, over 25 million chickens had either died of the infection or been euthanized in Iowa alone. Nebraska's toll at the same date was 7 million—a majority of the state's 9.45 million egg-laying hens.

### Table of infections

This table shows large bird farm infections during the 2015 outbreak. All birds affected either died of the H5N2 infection itself, or were destroyed as a precautionary measure. While 205 total infections were confirmed through June 1, only larger outbreaks (affecting >200,000 hens or >50,000 turkeys) are displayed here.
| Date detected | Location | Birds affected | Type |
| March 27 | Lac qui Parle County, Minnesota | 66,000 | Turkeys |
| April 1 | Beadle County, South Dakota | 50,600 | Turkeys |
| April 2 | Stearns County, Minnesota | 71,000 | Turkeys |
| April 4 | Stearns County, Minnesota | 76,000 | Turkeys |
| April 7 | Meeker County, Minnesota | 310,000 | Turkeys |
| April 8 | Kingsbury County, South Dakota | 71,900 | Turkeys |
| April 9 | Lyon County, Minnesota | 66,000 | Turkeys |
| April 10 | McPherson County, South Dakota | 55,200 | Turkeys |
| April 10 | McCook County, South Dakota | 54,700 | Turkeys |
| April 11 | Jefferson County, Wisconsin | 189,100 | Chickens |
| April 13 | Swift County, Minnesota | 160,000 | Turkeys |
| April 13 | Stearns County, Minnesota | 76,000 | Turkeys |
| April 14 | Swift County, Minnesota | 154,000 | Turkeys |
| April 14 | Redwood County, Minnesota | 56,000 | Turkeys |
| April 15 | Kandiyohi County, Minnesota | 152,000 | Turkeys |
| April 15 | Stearns County, Minnesota | 67,000 | Turkeys |
| April 15 | Roberts County, South Dakota | 66,600 | Turkeys |
| April 16 | Barron County, Wisconsin | 126,700 | Turkeys |
| April 20 | Osceola County, Iowa | 3,800,000 | Chickens |
| April 20 | Wadena County, Minnesota | 301,000 | Turkeys |
| April 20 | Kandiyohi County, Minnesota | 61,000 | Turkeys |
| April 21 | Kandiyohi County, Minnesota | 130,400 | Turkeys |
| April 21 | Kandiyohi County, Minnesota | 61,000 | Turkeys |
| April 21 | Stearns County, Minnesota | 53,900 | Turkeys |
| April 22 | Stearns County, Minnesota | 72,500 | Turkeys |
| April 22 | Kandiyohi County, Minnesota | 62,600 | Turkeys |
| April 22 | Kandiyohi County, Minnesota | 62,600 | Turkeys |
| April 22 | Meeker County, Minnesota | 58,900 | Turkeys |
| April 23 | Clay County, Minnesota | 408,500 | Chickens |
| April 23 | Chippewa County, Wisconsin | 56,500 | Turkeys |
| April 23 | Kandiyohi County, Minnesota | 54,300 | Turkeys |
| April 24 | Jefferson County, Wisconsin | 1,031,000 | Chickens |
| April 24 | LaMoure County, North Dakota | 71,500 | Mixed poultry |
| April 24 | Kandiyohi County, Minnesota | 67,000 | Turkeys |
| April 24 | Chippewa County, Minnesota | 64,900 | Turkeys |
| April 27 | Sioux County, Iowa | 1,603,900 | Chickens |
| April 27 | Barron County, Wisconsin | 83,300 | Turkeys |
| April 28 | Sioux County, Iowa | 3,660,000 | Chickens |
| April 28 | Osceola County, Iowa | 258,000 | Chickens |
| April 28 | Steele County, Minnesota | 82,900 | Turkeys |
| April 28 | Kandiyohi County, Minnesota | 50,900 | Turkeys |
| April 29 | Stearns County, Minnesota | 202,500 | Chickens |
| April 30 | Buena Vista County, Iowa | 449,100 | Turkeys |
| April 30 | Barron County, Minnesota | 96,500 | Turkeys |
| May 1 | Buena Vista County, Iowa | 4,910,600 | Chickens |
| May 4 | Madison County, Iowa | 1,495,600 | Chickens |
| May 5 | Wright County, Iowa | 2,821,800 | Chickens |
| May 5 | Nicollet County, Minnesota | 1,102,900 | Chickens |
| May 5 | Barron County, Wisconsin | 182,400 | Turkeys |
| May 5 | Swift County, Minnesota | 151,300 | Turkeys |
| May 5 | Kandiyohi County, Minnesota | 89,100 | Turkeys |
| May 5 | Pipestone County, Minnesota | 72,200 | Turkeys |
| May 5 | Barron County, Wisconsin | 57,200 | Turkeys |
| May 6 | Kandiyohi County, Minnesota | 65,000 | Turkeys |
| May 7 | Sioux County, Iowa | 309,900 | Chickens |
| May 7 | Osceola County, Iowa | 256,000 | Chickens |
| May 7 | Buena Vista County, Iowa | 52,900 | Turkeys |
| May 8 | Wright County, Iowa | 1,106,500 | Chickens |
| May 8 | Sioux County, Iowa | 581,300 | Chickens |
| May 8 | Sioux County, Iowa | 327,900 | Chickens |
| May 8 | Sioux County, Iowa | 303,100 | Chickens |
| May 11 | Swift County, Minnesota | 65,600 | Turkeys |
| May 12 | Dixon County, Nebraska | 1,791,500 | Chickens |
| May 12 | Wright County, Iowa | 966,600 | Chickens |
| May 13 | Hutchinson County, South Dakota | 70,600 | Turkeys |
| May 13 | Yankton County, South Dakota | 70,600 | Turkeys |
| May 14 | Lyon County, Iowa | 390,000 | Chickens |
| May 15 | Dixon County, Nebraska | 1,709,400 | Chickens |
| May 15 | Buena Vista County, Iowa | 903,700 | Chickens |
| May 15 | Sioux County, Iowa | 272,300 | Chickens |
| May 15 | Sioux County, Iowa | 240,000 | Chickens |
| May 18 | Moody County, South Dakota | 642,700 | Chickens |
| May 18 | Meeker County, Minnesota | 138,800 | Turkeys |
| May 19 | Renville County, Minnesota | 2,045,600 | Chickens |
| May 20 | Sioux County, Iowa | 240,000 | Chickens |
| May 21 | Sac County, Iowa | 100,000 | Turkeys |
| May 26 | Dixon County, Nebraska | 293,200 | Chickens |
| May 27 | Knox County, Nebraska | 3,000,000 | Chickens |
| May 27 | Adair County, Iowa | 974,500 | Chickens |
| May 27 | Renville County, Minnesota | 95,300 | Turkeys |
| May 28 | Wright County, Iowa | 991,500 | Chickens |
| May 28 | Kandiyohi County, Minnesota | 50,800 | Turkeys |
| June 1 | Wright County, Iowa | 434,800 | Chickens |
| June 1 | Moody County, South Dakota | 52,000 | Turkeys |
* ↑ Initially reported as 5.3 million birds; APHIS confirmation count was adjusted.
* ↑ Originally reported as 1.3 million birds; APHIS confirmation count was adjusted.
* ↑ Originally reported as 500,000 birds; APHIS confirmation count was adjusted.

## Control

When an infection was confirmed, all birds at the affected farm were destroyed per USDA guidelines. The birds were often culled by foam depopulation through pumping an expanding water-based foam into the barn houses, which suffocates them within minutes. The birds were then composted, usually at the location.