Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Infectious arthritis ?
    ### Response:
    Infectious arthritis is joint pain, soreness, stiffness and swelling caused by a bacterial, viral, or fungal infection that spreads from another part of the body. Depending on the type of infection, one or more joints may be affected. Certain bacteria can cause a form of infectious arthritis called reactive arthritis, which appears to be caused by the immune system reacting to bacteria, rather than by the infection itself.
    