Viral load in plasma. Blood was drawn at the indicated days, RNA was isolated from plasma, and purified viral RNA was quantified by real-time RT-PCR in specimens collected at alternate day (A) and daily (B) as described in “Quantitation of viral load with real-time RT-PCR.” The peak of dengue viremia in infected RM was from 3 to 7 days after infection. P.I. indicates postinfection.