Fever after the Coffee Farms

A 32-year-old man presents to an emergency department in Florida with 3 days of fever, chills, headache, diffuse myalgias, nausea, and poor oral intake. He returned 5 days ago from Colombia, where he spent 2 weeks visiting relatives and touring coffee farms in rural Tolima. He recalls frequent daytime mosquito bites while walking through shaded farm areas and nearby villages. He did not receive pre-travel vaccines because the trip was arranged on short notice.

He has no major medical history and takes no medications. He denies freshwater swimming, animal bites, unpasteurized dairy intake, new sexual exposures, injection drug use, or sick contacts. He took acetaminophen with partial relief. He has not taken aspirin or ibuprofen. On review of systems, he notes mild right upper quadrant discomfort and dark urine this morning, but no diarrhea, cough, rash, conjunctivitis, or bleeding.

On examination, temperature is 38.8 C, heart rate 96/min, blood pressure 118/72 mmHg, respiratory rate 16/min, and oxygen saturation 99% on room air. He appears tired but alert. There is faint scleral icterus and mild right upper quadrant tenderness without guarding. There is no hepatosplenomegaly, rash, lymphadenopathy, meningismus, conjunctival suffusion, or petechiae.

Laboratory studies show white blood cells 2.7 x 10^3/uL, platelets 108 x 10^3/uL, hemoglobin 14.9 g/dL, creatinine 1.1 mg/dL, total bilirubin 2.1 mg/dL, AST 312 U/L, ALT 196 U/L, alkaline phosphatase 94 U/L, and INR 1.2. Malaria thick and thin smears are negative. Dengue NS1 antigen and dengue IgM are negative. Hepatitis A IgM, hepatitis B surface antigen, hepatitis B core IgM, and hepatitis C antibody are negative. Blood cultures are pending.