Figure 1.

Schematic of the data and model. Animals are classified according to whether they are susceptible (S), exposed (i.e. infected but not yet infectious) (E), infectious (I) or recovered (R). The data provide the times of last negative, t _ln, and first positive, t _fp, samples, which provide constraints on the inferred infection time, t _I, and latent period, E. Similarly, the times of last positive, t _lp, and first negative, t _fn, constrain the infectious period, I.