Abstract:
Barley and cereal yellow dwarf viruses (B/CYDV) are a suite of aphid-vectored
pathogens that affect diverse host communities, including economically important
crops. Coinfection of a single host by multiple strains of B/CYDV can result in elevated
virulence, incidence, and transmission rates. We develop a model for a single
host, two pathogen strains, and n vector species, modeled by a system of nonlinear
ordinary differential equations. A single parameter describes the degree of relatedness
of the strains and the amount of cross-protection between them.
We compute the basic and type reproduction numbers for the model and analytically
prove the (conditional) stability of the disease-free equilibrium. We demonstrate
numerically that, although the basic reproduction number describes stability of the
disease-free equilibrium, the type reproduction numbers better describe the individual
behavior of each strain and the dynamics of coinfection. We then conduct a
sensitivity analysis on the components of the endemic equilibrium for two different
vector growth functions. Our results indicate that the disease transmission rates
and the vector birth and mortality rates are the most influential parameters for the
equilibrium prevalences of infection and coinfection.
