A 60-year-old man presents with a mild, intermittent fever and myalgia for three weeks. There is no history of night sweats or other constitutional symptoms. He consulted his primary care physician two weeks ago and was found to have a ulcer on his left leg at the time. A course of co-amoxiclav was prescribed, with no improvement. Closer questioning reveals that he returned from a trip to rural France a month ago, where he was camping and interacting with the local wildlife. His medical history is significant for type 2 diabetes mellitus well controlled on metformin. His family history is unremarkable. He does not smoke and drinks socially. There is no history of exposure to tuberculosis. A complete blood count is significant for a leukocyte count of 12,000/mm3 (normal: 4,500-11,000) with 80% neutrophils. A blood film shows no abnormal cells. C-reactive protein levels are normal.
Blood cultures are negative.
There are areas of focal necrosis surrounded by neutrophils and macrophages.
Tests for HIV, HSV, Lyme disease, VZV, Listeria monocytogenes, Bartonella henselae, Yersinia pestis, Bacillus anthracis, Rickettsia typhi are all negative.