<s>[INST] my 12 year old daughter was diagnosed with mono and she does not know how she got it. she has had fevers now for 4 days running from 100-102.5. How long is this going to last and is this condition dangerous. She does not want to eat and is tired. I am very worried! [/INST] Hi.... you need not worry about this. Infectious mononucleosis is caused by a virus called ABV. This is usually a self limiting viral infection. She will get better gradually. Nothing to worry about it.  She could have contracted it by aerosols from her friends at school or play areas. This might last for 7 to 14 days. Very rarely this is associated with neoplasm of the lymph nodes. But this is a very rare possibility. So do not worry. Regards -  </s>