A 19 years female recruit In the US Army was seen in the infirmary with a 3 day history of a "sore throat", malaise and headache of progressing severity. On examination her throat was erythematous without the presence of pustular or vesicular lesions. She had mild cervical lymphadenopathy and her temperature was 101F. No history of medication or other allergies was reported. what is your diagnosis at this time?