In 2015, an outbreak of avian influenza subtype H5N2 was identified in a series of

chicken The chicken (''Gallus gallus domesticus'') is a domesticated junglefowl species, with attributes of wild species such as the grey and the Ceylon junglefowl that are originally from Southeastern Asia. Rooster or cock is a term for an adu ...

and turkey farming operations in the

Midwestern United States The Midwestern United States, also referred to as the Midwest or the American Midwest, is one of four census regions of the United States Census Bureau (also known as "Region 2"). It occupies the northern central part of the United States. I ...

. 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 Iowa () is a U.S. state, state in the Midwestern United States, Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wiscon ...

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 California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

up 71% in the same timeframe. The virus was first identified in

Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over t ...

in early March. Prior to April 20, it affected commercial turkey farms almost exclusively, in the states of

Arkansas Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the O ...

Missouri Missouri is a state in the Midwestern region of the United States. Ranking 21st in land area, it is bordered by eight states (tied for the most with Tennessee): Iowa to the north, Illinois, Kentucky and Tennessee to the east, Arkansas t ...

North Dakota North Dakota () is a U.S. state in the Upper Midwest, named after the indigenous Dakota Sioux. North Dakota is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minnesota to the east, ...

South Dakota South Dakota (; Sioux: , ) is a U.S. state in the North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota and Dakota Sioux Native American tribes, who comprise a large po ...

Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...

, 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 The United States Department of Agriculture (USDA) is the federal executive department responsible for developing and executing federal laws related to farming, forestry, rural economic development, and food. It aims to meet the needs of comme ...

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 Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the sout ...

, 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 (affecting >200,000 hens or >50,000 turkeys) are displayed here.

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.

References

{{Reflist Disease outbreaks in the United States 2015 disease outbreaks 2015 disasters in the United States Influenza pandemics Avian influenza 21st-century epidemics History of the Midwestern United States