Figure 2

Changes in AIV-NP and H5-specific seropositivity over the course of 16 months after the arrival of H5N1. Sampling began on 28 January 2022 and continued until 25 April 2023. Arrows above the plot correspond to AIV detections in individuals sampled at that time point, with red arrows denoting when HPAIV (H5N1) was detected and blue arrows denoting LPAIV(s) was detected. Mean seropositivity along with standard error bars is shown. A hatched pattern is used for H5-specific seroprevalence to indicate that it overlays the AIV-NP seroprevalence. The two seronegative individuals sampled in February 2022 were removed from this week-by-week analysis as they were believed to have not been present at the time of the population-wide infection event (see Discussion). Additionally, the six individuals sampled on 23 August 2022 were also removed from this analysis as they were presumed to be primarily migratory individuals, coinciding with the large influx of individuals during this post-breeding migration period.