Avian Influenza mainly affects birds, but can also infect human beings and other animals. In humans, they lead to symptoms which are similar to flu, like fever, cough, muscle pain along with respiratory issues. To prevent its occurrence, contact between birds and humans must be reduced and infected birds must be culled.
Transmission Risks and Symptoms of H5N1 in Humans - Overview
Bird flu is a virus that primarily infects birds, but it can infect humans when individuals come into close contact with infected animals.

H7N9 Avian Influenza Virus Infection - Symptoms, Diagnosis, and Treatment
H7N9 avian influenza virus is the strain that causes bird flu in humans. Read the article to know more.