Mr. B., а 27-yeаr-оld mаle whо is HIV pоsitive, presents to the urgent care center with a history of cough, chills, malaise, and fatigue for the past week. Vital signs are within normal limits. He was relatively healthy prior to this and a purified protein derivative (PPD) test six months ago was negative. He was recently started on antiretroviral therapy. He is unsure of his CD4+ count but thinks it was decreasing. The most likely diagnosis is: