Review Question - QID 108582

A 21-year-old African-American male with a past medical history of recently diagnosed HIV (CD4: 145 cells/µL) presents to the emergency department with fatigue, sore throat, and dark urine. His home medications include his new HAART regimen of zidovudine, abacavir, and ritonavir as well as TMP-SMX for prophylaxis. His mother has a history of iron-deficiency anemia, and his younger sister was recently diagnosed with infectious mononucleosis. He is sexually active, and he recently returned from a trip to Vietnam. His temperature is 100.1°F (37.8°C), blood pressure is 126/76 mmHg, pulse is 88/min, and respirations are 16/min. On physical exam, he is noted to have conjunctival pallor, scleral icterus, pharyngeal erythema, and cervical lymphadenopathy. Laboratory tests are performed and reveal the following:

WBC: 7.9 x10^9/L
Hb: 10.1 g/dL
Hct: 28%
MCV: 82 fL
Plt: 312,000/µL

A peripheral blood smear is performed and can be seen in Figure A. What is most likely cause of this patient's symptoms?