I reassure you...
Children always look up to their mother during illnesses. It is a mother's smiling face that reduces their pain of illness.
So never ask too much questions in front of a child as he listens in his own way. Give him strength, always tell him that he or she would recover soon. We all get ill but with every illness our body become stronger. 
Your reassurance settles your child's anxiety, he suffers less and regains his appetite.
I reassure you, you reassure your child...