Egg Industry Center

Here are some answers to frequently asked questions concerning the avian influenza outbreak and its effects on eggs and egg products.

What is avian influenza (AI)?

Avian influenza (AI), a virus commonly known as the “bird flu,” is an infectious disease of birds caused by type A strains of the influenza virus.

What strains of AI are there?

There are both high-pathogenic and low-pathogenic strains of the disease. Pathogenicity refers to the ability of the virus to produce disease. High-pathogenic AI is the most virulent, infectious strain of the disease and is usually fatal to birds. Low-pathogenic AI may cause no symptoms at all in birds or only cause minor illness. The 2015 outbreak that resulted in the loss of so many birds was a high-path strain of AI.

When was AI last identified in commercial egg laying hens in the U.S.?

June 2015 was the most recent detection of AI in a U.S. commercial egg laying flock.

What happened in the 2015 AI outbreak?

The devastating and rapid spread of highly pathogenic (HP) Avian Influenza (AI) in early 2015 was one of the worst crises to face the egg farming community.

  • Between November 2014 and June 2015, more than 48 million total birds (48,091,293) were affected in 223 AI-positive flocks in the U.S. 


  • In 2015, hens on 26 commercial egg farms tested positive for AI in Iowa, Minnesota, Nebraska, South Dakota and Wisconsin, totaling more than 35 million laying hens and six million pullets (young birds not yet in production). This calculated to about 12 percent of all laying hens in the U.S. and more than 30 percent of the layers dedicated for the egg products business. 


  • June 2015 was the last detection of high pathogenic avian influenza in the commercial egg laying flock in the U.S.

How is AI transmitted?

It is believed AI is transmitted through wild birds and waterfowl, either through direct contact with other birds or indirectly. Researchers and scientists continue to evaluate other ways the disease may be spreading.

Is AI a risk to public health? Can humans contract the disease?

The identified strains of AI found on U.S. egg and turkey farms have not affected any humans and are not considered a risk to public health.

How are farmers handling disease prevention?

U.S. egg farmers have implemented extensive biosecurity measures and taken every precaution to protect their flocks, including restricting farm access, preventing exposure to wild and migratory birds, increasing veterinary monitoring and using protective gear at all times. For more about on-farm biosecurity measures in the egg industry see these updates on disease prevention from United Egg Producers.

What if AI reappears in U.S. commercial poultry flocks?

We cannot predict anything as it relates to AI, as this is truly an act of nature. The egg industry has worked closely with state and federal officials on key AI response issues. Since the 2015 AI outbreak, U.S. egg farmers have made significant increases to biosecurity measures on their farms to protect their flocks. Comprehensive disease prevention protocols on commercial eggs farms include, but are not limited to, restricting farm access, preventing hens from exposure to wild and migratory birds, increasing veterinary monitoring of flocks and using protective gear at all times.

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