Effect of Heterogeneous Mixing and Vaccination on the Dynamics of Anthelmintic Resistance: A Nested Model
Figure 2
Allele frequency in worms outside of the primary focus of resistance.
Resistance can be fully recessive (A–B) or fully dominant (C–D). Annual chemotherapy is administered to 50% of the host population and no vaccination. Simulation parameters in Table 1. A) If resistance is a recessive character the allele frequency follows two different time-dynamics depending on the the degree of host-population mixing ρ: i) for ρ smaller than 69%, it grows fast and plateaus at a level inversely related to the value of ρ; ii) for ρ equal to or larger than 69%, a slow initial growth is followed by an accelerated growth. B) Non-monotonic relation between the allele frequency after 20 annual chemotherapy rounds and ρ. The maximum allele frequency is observed when ρ is equal to 85%. C) If resistance is a dominant character, the allele frequency grows at a rate inversely related to ρ. D) Negative monotonic relationship between the allele frequency after 20 annual chemotherapy rounds and ρ. The maximum allele frequency is observed when ρ is equal to 1.99% (homogeneous mixing case).