Figure 1

Conceptual diagram of the model combining population and infection dynamics. All health states are: susceptible (S), no longer susceptible (R), infected and transiently slightly infectious (I_T), latently infected (I_L), infected and moderately infectious (I_M), and infected and highly infectious (I_H). Solid arrows represent transitions between health states; dashed arrows represent the animals’ contribution to their local environment; w: week; t: week number in the year; a: age in weeks; env: environment.