Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Rubella ?
    ### Response:
    Rubella is an infection caused by a virus. It is usually mild with fever and a rash. About half of the people who get rubella do not have symptoms. If you do get them, symptoms may include       - A rash that starts on the face and spreads to the body    - Mild fever    - Aching joints, especially in young women    - Swollen glands       Rubella is most dangerous for a pregnant woman's baby.
    