Fig 1.

Comparison of site-specific RT-PCR and Sanger sequencing. (A) Site-specific RT-PCR on RNA isolated from cloacal swabs from one duck in group two (2.3) inoculated with A/Mallard/182742/1998 and access to OC at 1,000 ng/liter on days 2 to 6 postinoculation using wild-type primers showing detection of wild-type E119 on all days; (B) site-specific RT-PCR on the same RNA from panel A using E119V resistant primers showing the detection of E119V on days 5 and 6; (C) chromatograms of DNA sequenced from the same duck as that in panels A and B on days 4 to 6 postinoculation showing the visible mutation on day 5 as a small subpopulation, compared with the faint band on day 5 in panel B and as the dominant population on day 6.