2015 United States H5N2 outbreak

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.