Infectious work up
Not sensitive or specific
CBC- can show anemia and thrombocytopenia
LFTs- often elevated 3-5x normal
Lumbar puncture- resembles aseptic meningitis
Not sensitive or specific
CBC- can show anemia and thrombocytopenia
LFTs- often elevated 3-5x normal
Lumbar puncture- resembles aseptic meningitis
Immunofluorescent assay is the gold standard
Becomes diagnostic with time.  Rarely positive at onset of illness.
PCR
Becomes diagnostic with time.  Rarely positive at onset of illness.
Murine typhus
Non-specific viral illness
Rat bite fever
Most common admitting diagnosis in one case study was "fever of unknown origin"[2]
Epidemic typhus
Babesiosis
Drug fever
Colorado tick fever