Review Question - QID 108604

A 24-year-old woman with no significant medical history presents to the emergency department for progressive shortness of breath. She endorses decreased exercise tolerance as well as intermittent palpitations. She returned from a recent missionary trip to South America 12 months prior where she endorsed eating a local delicacy as well as a period of fevers and eyelid swelling during her stay. Her temperature is 99.1°F (37.3°C), pulse is 95/min, blood pressure is 130/85 mmHg, respirations are 15/min, and oxygen saturation is 97% on room air. Physical exam is notable for a laterally displaced point of maximal impulse as well as a 2/6 diastolic murmur radiating to the axilla. A blood smear is shown in Figure A. Her laboratory results are:

Leukocyte count and differential:
Leukocyte count: 10,000/mm^3
Neutrophils: 57%
Lymphocytes: 30%
Monocytes: 3%
Eosinophils: 9%
Basophils: 1%
Hemoglobin: 13.1 g/dL
Platelet count: 420,000/mm^3

Which of the following is the most appropriate treatment?