Question: Here's the story: One evening three weeks ago, I was beset by severe fatigue that kept me inactive for about a week. Over this week-long period of mostly bed-rest and no significant exercise, I also began suffering uncharacteristic lower back pain extending to the hamstrings of both legs; it felt as if I had severely over-exercised (though I had not). After the first week concluded the fatigue resolved, but the pain persisted into the second week. During the second week, I began suffering chills and a low grade fever of about 99 starting in the afternoon, and rising to 100 - 100.5 by late evening. One morning during the second week, I awoke and found that the lower back/hamstring pain had completely resolved. But the chills and low grade fever persisted, and shortly thereafter I began experiencing moderate daily night sweats. The chills, fever and night sweats have persisted into the third week, and are my only current symptoms. I have no swollen lymph nodes, no aches & pains, no respiratory symptoms, no fatigue, and a normal appetite. My eyes are clear; I look healthy. But for the chills, fever and night sweats, I feel fine. Can you suggest a possible diagnosis? Note one observation: A day before the onset of symptoms in the first week, I awoke with a large apparent bite on my left thigh, with no redness or discoloration, that itched for several days before resolving. Besides that, I know of no other abnormalities. I'm a 46 year old male, heretofore in excellent health, and generally fit. I take no medication.