Figure 17. The number of human cases with time under the situation that there exists human-to-human transmission when domestic poultry are viewed as the original infection source.

(a) β_hh = 5 × 10⁻⁹, β₁ = 7.045 × 10⁻⁸, β₂ = 8 × 10⁻¹⁶; (b) β_hh = 10 × 10⁻⁹, β₁ = 7.969 × 10⁻⁸, β₂ = 1.45 × 10⁻¹⁶. p = 1.7.