Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Aspergillosis ?
    ### Response:
    Aspergillosis is a disease caused by a fungus (or mold) called Aspergillus. The fungus is very common in both indoors and outdoors. Most people breathe in the spores of the fungus every day without being affected. But some people get the disease. It usually occurs in people with lung diseases or weakened immune systems.
    