A man with fever and lymphadenopathy.

A 40-year-old man presented with a three-week history of malaise, nausea, night sweats, decreased appetite, and a 15-lb weight loss. He reported having had diarrhea, occasionally with bright red blood, for the first two weeks and a temperature as high as 39.4 degrees C for the last two weeks. He had not had cough, shortness of breath, wheezing, chest pain, arthralgias, rash, or conjunctivitis. He had not eaten raw oysters or raspberries.