Figure 1. Mean shedding of H4N6 AIV RNA by mallards infected via oral inoculation or water transmission.

(A) Cloacal shedding, (B) Oropharyngeal shedding. RRT-PCR was used to detect and quantify viral RNA in cloacal and oropharyngeal swabs. Values were extrapolated from a standard curve and presented as PCR EID₅₀ equivalents/mL on a log scale. Each point represents the arithmetic mean of 6 mo mallards (n = 11) or 3 mo mallards (n = 12). On average, the shedding curves differed between 6 mo and 3 mo mallards. The dashed line represents our RRT-PCR threshold of detection as 10⁰ PCR EID₅₀ equivalents/mL.