A 9-year-old boy is brought to the physician for a 2-day history of worsening shortness of breath and dry cough. Temperature is 101 F. He had a left renal transplant performed one year ago for chronic pyelonephritis secondary to recalcitrant vesicoureteral reflux. A lung biopsy is shown.
Which of the following is the most likely diagnosis?
Bacterium
DNA virus
Fungus
Malignancy
RNA virus
