Effect of Heterogeneous Mixing and Vaccination on the Dynamics of Anthelmintic Resistance: A Nested Model

TL;DR

This study uses computer simulations to explore how host mixing and vaccination strategies influence the spread of anthelmintic resistance, highlighting the importance of targeted vaccines and population dynamics in control efforts.

Contribution

It introduces a nested model simulating host, parasite, and gene interactions to analyze resistance dynamics under different mixing and vaccination scenarios.

Findings

Resistance dynamics depend on host mixing and gene dominance.

Vaccines targeting adult parasites are more effective at reducing resistance.

Different resistance regimes emerge based on genetic and population factors.

Abstract

Anthelmintic resistance is a major threat to current measures for helminth control in humans and animals. The introduction of anthelmintic vaccines, as a complement to or replacement for drug treatments, has been advocated as a preventive measure. Here, a computer-based simulation, tracking the dynamics of hosts, parasites and parasite-genes, shows that, depending on the degree of host-population mixing, the frequency of totally recessive autosomes associated with anthelmintic resistance can follow either a fast dynamical regime with a low equilibrium point or a slow dynamical regime with a high equilibrium point. For fully dominant autosomes, only one regime is predicted. The effectiveness of anthelminthic vaccines against resistance is shown to be strongly influenced by the underlying dynamics of resistant autosomes. Vaccines targeting adult parasites, by decreasing helminth fecundity or lifespan, are predicted to be more effective than vaccines targeting parasite larvae, by decreasing host susceptibility to infection, in reducing the spread of resistance. These results may inform new strategies to prevent, monitor and control the spread of anthelmintic resistance, including the development of viable anthelmintic vaccines.