Symptoms: sick chickens are depressed, feed consumption is reduced, and they are thin; The nesting ability of hens is enhanced and the egg production is reduced; Mild to severe respiratory symptoms, including coughing, sneezing and profuse tears; Head and face edema, nervous disorder, diarrhea.

Human infection with avian influenza is a human disease caused by avian influenza virus. Avian influenza virus belongs to influenza A virus. According to the pathogenicity of avian influenza virus to chickens and turkeys, it is divided into three grades: high, medium, low/no pathogenicity. Because of the characteristics of hemagglutinin structure of avian influenza virus, it usually infects poultry. When the virus rearranges its genes and changes its structure in the process of replication, it may cause people to be infected with avian influenza.