A theoretical model of coinfection dynamics: Modeling competition dynamics between Borrelia burgdorferi and Anaplasma phagocytophilum within a human host

Though many mathematical models have been used in the field of epidemiology, few of them aim to predict the outcome of competitive coinfection dynamics within humans. This study created a theoretical model to analyze the competition dynamics between two the infectious bacteria, Borrelia burgdorferi and Anaplasma phagocytophilum, within a human host. Interactions between two bacterial species in the human body are complex due to both microorganisms competing for the same resource and eliciting the body's innate immune response at different rates. The goal of this study was to identify whether resource limitation or increased immune responses would be more efficient in clearing this specific coinfection scenario. Iron was the resource chosen for this study, and the populations of neutrophils and macrophages within our model represented the innate immune system. Literature values were used to parameterize the interactions for numerical simulations. Results showed that a 61% decrease in iron availability below baseline parameters would clear the coinfection, while a 137% increase in neutrophils would produce the same results. Applying these two methods simultaneously showed improved results, where only a 45% reduction in iron along with a 45% amplification of neutrophils was equally efficient at clearing the coinfection. The results showed that these changes have the potential to be artificially induced in humans as an alternative treatment method to antibiotics for coinfection scenarios.