Anaplasmosis is a tick-borne illness transmitted by the Ixodes scapularis tick in the Northeast and Midwest regions of the United States. Clinical symptoms of anaplasmosis can be non-specific, which may delay the diagnosis. This is a case of a 73-year-old male from South Florida who initially presented with non-specific febrile illness to an urgent care and was initially treated for a viral infection. Persistent febrile episodes prompted presentation to the emergency room. Initial findings of pancytopenia and fever worsened after the initiation of broad-spectrum antibiotics. Upon further history, the patient recounted recent travel to upstate New York and Canada, prompting a switch to intravenous doxycycline therapy for the presumptive diagnosis of tick-borne disease. Definitive diagnosis of anaplasmosis was confirmed via polymerase chain reaction. Since discharge with doxycycline therapy, the patient's symptoms and pancytopenia have fully resolved. Conducting a complete history and physical examination with concurrent laboratory studies is imperative for accurate diagnoses and improvement in patient outcomes.
Keywords: anaplasma phagocytophilum; fever; human granulocytic anaplasmosis; ixodes scapularis; pancytopenia; tick-borne illness.
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