Figure 2.

Seroprevalence and prevalence of IAV infection by age among pigs on finishing and farrow-to-finish farms. (a) The model-predicted mean seroprevalence of influenza by age (1–24 weeks of age) is plotted (coloured lines) for finish farms and farrow-to-finish farms with 1500 finishing pigs for values of R₀ from 1.5 to 5. The circles represent the mean seroprevalence of H1N1 (black), H1N2 (light grey) and H3N2 (dark grey) antibodies observed among finishing pigs in The Netherlands (for farms of all sizes), while the lines are the corresponding 95% CIs. (b) The model-predicted mean prevalence of IAV is plotted by age (1–24 weeks of age) for finishing and farrow-to-finish farms. Births and the movement of pigs from one site to the next are assumed to occur every three weeks.