Figure 2.

Diagram of the canine rabies model with three dog ownership types. Type i = (1, 2, 3) represent stray dogs; owned free-roaming dogs; and owned confined dogs, respectively. The bullets represent the natural death rates b_i. Infection of susceptible dogs occurs at a rate λ_i = β_i1I₁ + β_i2I₂ + β_i3I₃, also known as the force of infection. Stray dogs (type 1) face an additional density-dependent mortality at rate γN₁. See Table 1 for parameter meanings.