Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Beriberi ?
    ### Response:
    Beriberi is a condition that occurs in people who are deficient in thiamine (vitamin B1). There are two major types of beriberi: wet beriberi which affects the cardiovascular system and dry beriberi which affects the nervous system. People with wet beriberi may experience increased heart rate, shortness of breath, and swelling of the lower legs.
    