@ehBeth,
ehBeth wrote:You wouldn't hear that in most English-speaking countries. It sounds like an old-fashioned bit of dialect.
Which? I have the flu, I have flu, or I've got flu?
I would localise using 'the' before certain disease names in time, to the 19th and early 20th centuries. Some rather dubious grammar guides, however, allege that you have to use 'the' for certain diseases: the measles, the flu, the mumps, the bubonic plague. (The list varies.) I would differ and say it is optional but only for certain diseases, common childhood ones, perhaps. Nobody says (I think), or said, "I've got the cancer" or "the typhoid". There is a Northern English children's playground chant that starts "I had the scarlet fever, I had it very bad". Also, in Little Women by Louisa May Alcott, Jo says to Beth: "You've had the scarlet fever, haven't you?". (Poor Beth! I found her death very affecting at the age of 9.)