Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Diphtheria ?
    ### Response:
    Diphtheria is a serious bacterial infection. You can catch it from a person who has the infection and coughs or sneezes. You can also get infected by coming in contact with an object, such as a toy, that has bacteria on it.    Diphtheria usually affects the nose and throat.
    