Figure 2.

Electrophoretic gel used to determine the presence or absence of a 101‐base pair PCR product corresponding to the influenza A M1 matrix gene. The PCR products for the NOP swabs, cough aerosols, and exhalation aerosols for three test subjects are shown. (+) indicates the sample is positive for influenza A. (−) indicates the sample is negative. The PCR products for the cough and exhalation samples for subject FC178 were confirmed to be from the influenza A M1 matrix gene by DNA sequence analysis. The negative control contained all PCR reagents, primers, and probe but no template. The positive control contained 10⁴ M1 copies and was run in parallel with the experimental samples.