title: The impact of coinfections and their simultaneous transmission on antigenic diversity and epidemic cycling of infectious diseases.
abstract: Epidemic cycling in human infectious diseases is common; however, its underlying mechanisms have been poorly understood. Much effort has been made to search for external mechanisms. Multiple strains of an infectious agent were usually observed and coinfections were frequent; further, empirical evidence indicates the simultaneous transmission of coinfections. To explore intrinsic mechanisms for epidemic cycling, in this study we consider a multistrain Susceptible-Infected-Recovered-Susceptible epidemic model by including coinfections and simultaneous transmission. We show that coinfections and their simultaneous transmission widen the parameter range for coexistence and coinfections become popular when strains enhance each other and the immunity wanes quickly. However, the total prevalence is nearly independent of these characteristics and approximated by that of one-strain model. With sufficient simultaneous transmission and antigenic diversity, cyclical epidemics can be generated even when strains interfere with each other by reducing infectivity. This indicates that strain interactions within coinfections and cross-immunity during subsequent infection provide a possible intrinsic mechanism for epidemic cycling.
authors.affiliation: Department of Statistics, Modelling and Economics, Centre for Infectious Disease Surveillance and Control, Public Health England, 61 Colindale Avenue, London NW9 5EQ, UK ; Medical Research Council Centre for Outbreak Analysis and Modelling, Department of Infectious Disease Epidemiology, Imperial College Faculty of Medicine, Norfolk Place, London W2 1PG, UK.
authors.forename: Xu-Sheng
authors.initials: XS
authors.lastname: Zhang
authors.affiliation: Centre for Nonlinear Complex Systems, Department of Physics, Yunnan University, Kunming, Yunnan 650091, China.
authors.forename: Ke-Fei
authors.initials: KF
authors.lastname: Cao
mesh_terms: D000940:Antigenic Variation / Q000276:immunology; D060085:Coinfection / Q000453:epidemiology*; D003141:Communicable Diseases / Q000453:epidemiology* / Q000473:pathology / Q000635:transmission; D006801:Humans; D018448:Models, Immunological; D008962:Models, Theoretical