Nausea, Muscle Stiffness, Lack Of Appetite, Nosebleed. Any Idea?

My 21 year old son is in excellent health. Last Thursday, he developed nausea and muscle stiffness . The next day, still nauseated, muscle stiffness with probably low-grade temp. Lack of appetite through the weekend. On Monday, he went to campus clinic at TAMU. CBC, UA and West Nile Screen ordered. He was still fatigued yesterday but muscle pain in lower lumbar area. Today, he had a sudden onset of nosebleed. He has not had cough, sneeze or congestion . CBC and UA came back normal. No west Nile results until next week. Any ideas on these symptoms?