A 57-year-old woman was referred as an inpatient for a fever of > 3 months in duration. Despite previous extensive inpatient evaluation, the cause of fever could not be identified. She did not respond to multiple courses of IV broad-spectrum antibiotics. She did not smoke, drink alcohol, or use illicit drugs. She had no recent travel, no exposure to animals, and no known insect or tick bites. Her three other family members remained well. She did not have any respiratory symptoms.