Avian Influenza (Bird Flu)

J. P. Jacob, G. D. Butcher, F. B. Mather, and R. D. Miles

This document provides an overview of avian influenza in poultry, detailing its history, clinical signs, transmission, and prevention. Avian influenza is a viral disease affecting birds' respiratory, digestive, and nervous systems, with varying pathogenicity. Original publication date April 1998.

Ashley McLeod-Morin, Benjamin D. Anderson, Glenn Morris, C. Sanders, Colleen Larson, Ricky Telg, andAnnabel Henson

Bird flu is caused by the H5N1 subtype of influenza A virus. This publication aims to help consumers better understand bird flu and ways bird flu may impact consumable products, such as eggs or milk. Written by A. McLeod-Morin, B. D. Anderson, G. Morris, C. Sanders, C. Larson, R. Telg, and A. Henson, and published by the UF/IFAS Department of Animal Sciences, September 2025.

Bridget B. Baker and Samantha M. Wisely

Avian influenza is a highly contagious respiratory virus that circulates globally among wild birds. As of July 2022, H5N1 has spread quickly in the United States, killing wild birds in more than 40 states and impacting more than 60 species. While lethal to many bird and some mammal species, the current circulating strain is not particularly infectious in humans.  Nonetheless, basic precautions are still warranted, particularly for those people in contact with wild birds via hunting or the use of backyard bird feeders or baths, as well as people with backyard poultry or pet birds. These basic precautions are detailed.