Specificity and sensitivity of detection of DV RI-RNA in the viral stock solution by RT-PCR. (A) Stock solutions containing 2 × 107 DEN-2 particles (lanes 1 and 2) and supernatant from noninfected C6/36 cells (lanes 3 and 4) were analyzed by looking for positive (lanes 1 and 3) and negative (lanes 2 and 4) strands. (B) Dilutions from the stock solutions containing 1,000 (lane 1), 100 (lane 2), 10 (lane 3), 1 (lane 4), and 0.1 (lane 5) DEN-2 particles and the supernatant from noninfected C6/36 cells (lane 6) were analyzed by looking for positive strands. Lane MW, molecular size marker (100-bp ladder).