Figure 3.

(Panel A). The percent positive samples using the two-step nested polymerase chain reaction (PCR) technique. The reverse transcription-PCR (RT-PCR) is the first step and is a qualitative assessment of viral load (black bars). Samples positive by RT-PCR represent a higher viral load then samples only positive in the second nested PCR step (grey bars). (Panel B) Quantitative PCR using extracted RNA from tittered viruses. Results are expressed as plaque-forming unit (PFU)/mL. Error bars represent the upper standard error of the mean.