Figure 2
Age at the onset of clinical signs. (A) Age at onset and its dependence on genotype and time since the first case in the outbreak. The observed age at onset is shown for each genotype: VRQ/VRQ (black squares), VRQ/ARQ (grey circles), VRQ/ARR (grey downward triangles) and unknown (white upward triangles). A fitted trend line is also shown. (B) Kaplan-Meier estimates of the survivor function for the age at onset (in months) in VRQ/VRQ and VRQ/ARQ animals.