Influenza: An idea model bridging epidemiological and evolutionary dynamics

Abstract

Annual outbreaks of influenza cause substantial morbidity and mortality, and also cause heavy economic losses. In recent years the threat of a human influenza pandemic has increased considerably as humans have become susceptible to infection by the avian influenza virus H5N1. However, our current understanding of influenza and the ability to evaluate the threat are limited. Several important issues, including the influence of climate variability on influenza epidemic patterns and intraspecific and interspecific interactions between various circulating influenza types, subtypes and strains, have not yet been sufficiently studied. In this study, we explored the immunological dynamics and epidemiological dynamics of influenza using our host immune unit-virus-susceptible (HVS) model. By matching model output to epidemiological patterns identified in surveillance data collected from United States, we found that three types of interspecific competitions (between influenza A and B, influenza A subtypes H1 and H3, and new and circulating strains) are essential to depict phylogenetic patterns of influenza. The study therefore, illustrates the population dynamics of the emergence, circulation and elimination of new influenza variants (subtypes or strains).