A 32-year-old man from Mumbai presents to the STI clinic with a 2-week history of fever, generalized lymphadenopathy, and a maculopapular rash over the trunk. He reports unprotected sexual contact with multiple partners over the past 3 months. On examination, he has cervical and axillary lymphadenopathy, hepatosplenomegaly, and oral candidiasis. His CD4+ count is 450 cells/µL. Rapid HIV antibody test is negative, but HIV RNA (viral load) is 850,000 copies/mL. What is the most likely explanation for this clinical presentation?