In a recent episode of the Small Farm Sustainability Podcast, Yuko Sato, Iowa State University Extension and Outreach poultry veterinarian and associate professor in Iowa State's College of Veterinary Medicine, discusses avian influenza and how good biosecurity practices can help prevent outbreaks in poultry.

Avian influenza, explains Sato, is a viral disease of poultry and other birds caused by type A influenza virus. There are two primary types of the virus, distinguished by their capacity to cause disease. The first, Low-Pathogenic Avian Influenza, results in mild respiratory symptoms. The second, and more concerning, is Highly Pathogenic Avian Influenza, which spreads rapidly through chicken and turkey populations and has a high fatality rate.
According to Sato, HPAI can have a variety of symptoms. Many birds experience respiratory symptoms, such as coughing, sneezing, nasal discharge and swollen sinuses. Other symptoms include diarrhea, flock huddling, decreased food and water consumption and neurological symptoms such as lethargy and depression. The biggest red flag, however, is sudden and unexplained death within the flock.