A 32-year-old woman comes to the ED with a previous month long history of malaise, mild cough, and subjective fevers.
She is HIV positive and her last CD4 count taken 6 months prior was 220. She's not on antiretroviral therapy or other medications.
Vital signs: HR= 88 beats per minute, BP=130/60 mm Hg, RR = 12 breaths per minute, oxygen sat= 91% on room air.
Her chest radiograph shows diffuse, patchy infiltrates bilaterally. Subsequent labs are unremarkable except for an elevated lactate dehydrogenase level.
What most likely causing her condition?
Select one of the following: