Below is an instruction from Human. Write a response.
    ### Instruction:
    How to diagnose Viral Gastroenteritis ?
    ### Response:
    Viral gastroenteritis is usually diagnosed based on symptoms alone. People who have symptoms that are severe or last for more than a few days may want to see a health care provider for additional tests. A health care provider may ask for a stool sample to test for rotavirus or norovirus or to rule out bacteria or parasites as the cause of the gastroenteritis.
    