Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Bird Flu ?
    ### Response:
    Birds, just like people, get the flu. Bird flu viruses infect birds, including chickens, other poultry, and wild birds such as ducks. Most bird flu viruses can only infect other birds. However, bird flu can pose health risks to people. The first case of a bird flu virus infecting a person directly, H5N1, was in Hong Kong in 1997.
    