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 region of the 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. No human cases have been reported, and human infection is almost impossible.

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. This infection would be the first in a series at large hen operations in Iowa, Nebraska, and other 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 are displayed here.
Date detectedLocationBirds affectedTypeSource
March 27Lac Qui Parle County, Minnesota66,000Turkeys
April 1Beadle County, South Dakota50,600Turkeys
April 2Stearns County, Minnesota71,000Turkeys
April 4Stearns County, Minnesota76,000Turkeys
April 7Meeker County, Minnesota310,000Turkeys
April 8Kingsbury County, South Dakota71,900Turkeys
April 9Lyon County, Minnesota66,000Turkeys
April 10McPherson County, South Dakota55,200Turkeys
April 10McCook County, South Dakota54,700Turkeys
April 11Jefferson County, Wisconsin189,100Chickens
April 13Swift County, Minnesota160,000Turkeys
April 13Stearns County, Minnesota76,000Turkeys
April 14Swift County, Minnesota154,000Turkeys
April 14Redwood County, Minnesota56,000Turkeys
April 15Kandiyohi County, Minnesota152,000Turkeys
April 15Stearns County, Minnesota67,000Turkeys
April 15Roberts County, South Dakota66,600Turkeys
April 16Barron County, Wisconsin126,700Turkeys
April 20Osceola County, Iowa3,800,000Chickens
April 20Wadena County, Minnesota301,000Turkeys
April 20Kandiyohi County, Minnesota61,000Turkeys
April 21Kandiyohi County, Minnesota130,400Turkeys
April 21Kandiyohi County, Minnesota61,000Turkeys
April 21Stearns County, Minnesota53,900Turkeys
April 22Stearns County, Minnesota72,500Turkeys
April 22Kandiyohi County, Minnesota62,600Turkeys
April 22Kandiyohi County, Minnesota62,600Turkeys
April 22Meeker County, Minnesota58,900Turkeys
April 23Clay County, Minnesota408,500Chickens
April 23Chippewa County, Wisconsin56,500Turkeys
April 23Kandiyohi County, Minnesota54,300Turkeys
April 24Jefferson County, Wisconsin1,031,000Chickens
April 24LaMoure County, North Dakota71,500Mixed poultry
April 24Kandiyohi County, Minnesota67,000Turkeys
April 24Chippewa County, Minnesota64,900Turkeys
April 27Sioux County, Iowa1,603,900Chickens
April 27Barron County, Wisconsin83,300Turkeys
April 28Sioux County, Iowa3,660,000Chickens
April 28Osceola County, Iowa258,000Chickens
April 28Steele County, Minnesota82,900Turkeys
April 28Kandiyohi County, Minnesota50,900Turkeys
April 29Stearns County, Minnesota202,500Chickens
April 30Buena Vista County, Iowa449,100Turkeys
April 30Barron County, Minnesota96,500Turkeys
May 1Buena Vista County, Iowa4,910,600Chickens
May 4Madison County, Iowa1,495,600Chickens
May 5Wright County, Iowa2,821,800Chickens
May 5Nicollet County, Minnesota1,102,900Chickens
May 5Barron County, Wisconsin182,400Turkeys
May 5Swift County, Minnesota151,300Turkeys
May 5Kandiyohi County, Minnesota89,100Turkeys
May 5Pipestone County, Minnesota72,200Turkeys
May 5Barron County, Wisconsin57,200Turkeys
May 6Kandiyohi County, Minnesota65,000Turkeys
May 7Sioux County, Iowa309,900Chickens
May 7Osceola County, Iowa256,000Chickens
May 7Buena Vista County, Iowa52,900Turkeys
May 8Wright County, Iowa1,106,500Chickens
May 8Sioux County, Iowa581,300Chickens
May 8Sioux County, Iowa327,900Chickens
May 8Sioux County, Iowa303,100Chickens
May 11Swift County, Minnesota65,600Turkeys
May 12Dixon County, Nebraska1,791,500Chickens
May 12Wright County, Iowa966,600Chickens
May 13Hutchinson County, South Dakota70,600Turkeys
May 13Yankton County, South Dakota70,600Turkeys
May 14Lyon County, Iowa390,000Chickens
May 15Dixon County, Nebraska1,709,400Chickens
May 15Buena Vista County, Iowa903,700Chickens
May 15Sioux County, Iowa272,300Chickens
May 15Sioux County, Iowa240,000Chickens
May 18Moody County, South Dakota642,700Chickens
May 18Meeker County, Minnesota138,800Turkeys
May 19Renville County, Minnesota2,045,600Chickens
May 20Sioux County, Iowa240,000Chickens
May 21Sac County, Iowa100,000Turkeys
May 26Dixon County, Nebraska293,200Chickens
May 27Knox County, Nebraska3,000,000Chickens
May 27Adair County, Iowa974,500Chickens
May 27Renville County, Minnesota95,300Turkeys
May 28Wright County, Iowa991,500Chickens
May 28Kandiyohi County, Minnesota50,800Turkeys
June 1Wright County, Iowa434,800Chickens
June 1Moody County, South Dakota52,000Turkeys

Control

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