A Host-Parasite System with Multiple Parasite Strains and Superinfection Revisited: The Global Dynamics

Lili Liu1,2, Xinzhi Ren1, Xianning Liu3

  • 1Key Laboratory of Eco-Environments in Three Gorges Reservoir Region (Ministry of Education), School of Mathematics and Statistics, Southwest University, Chongqing, 400715, China.

Acta Biotheoretica
|September 1, 2019
PubMed

Insights

This study analyzes host-parasite dynamics with multiple strains, relaxing previous assumptions. We identify key reproduction numbers for parasite extinction and coexistence, revealing surprising global stability in multi-strain systems.

Area of Science:

  • Mathematical Biology
  • Epidemiology
  • Theoretical Ecology

Background:

  • Revisiting the Nowak and May host-parasite model with multiple parasite strains and superinfection.
  • Relaxing two strict conditions previously imposed on the system dynamics.

Purpose of the Study:

  • To investigate the global dynamics of a generalized host-parasite system with multiple parasite strains.
  • To determine threshold conditions for parasite extinction and strain coexistence.
  • To analyze the stability of equilibrium points in multi-strain host-parasite interactions.

Main Methods:

  • Mathematical modeling of host-parasite interactions.
  • Analysis of differential equations to determine global dynamics.
  • Derivation and application of basic reproduction number and invasion reproduction number.
  • Numerical simulations to validate theoretical findings.

Main Results:

  • For two parasite strains, the basic reproduction number (R0) determines extinction, while the invasion reproduction number (Rinv) governs coexistence.
  • For three parasite strains, global stability of both parasite-free and coexistence equilibria was unexpectedly found.
  • Global asymptotic stability of the parasite-free equilibrium was established for n strains.
  • A conjecture on the general global stability of coexistence equilibrium for n strains was proposed and supported by numerical examples.

Conclusions:

  • The study provides a more comprehensive understanding of host-parasite dynamics under relaxed conditions.
  • Key reproduction numbers are identified as critical for predicting disease persistence and co-circulation.
  • The findings highlight the complex stability properties of multi-strain parasite systems, with implications for disease control strategies.

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