Khong, V. H. | Search bioRxiv

bioRxiv2026

Evolution of pathogen dormancy in fluctuating environments

Dormancy is a widespread life-history strategy that enables organisms to persist through periods of adverse environmental conditions. Despite its prevalence, the evolutionary forces shaping dormancy and the timing of reactivation remain poorly understood, particularly in pathogens facing predictable environmental fluctuations. Here, we investigate how seasonal variation can drive the joint evolution of pathogen dormancy and reactivation, and whether these traits are favoured to evolve as fixed or plastic strategies. Using a theoretical model of vector-borne disease transmission, we show when seasonality can promote plasticity in dormancy and reactivation. The optimal timing of transitions between active and dormant states depends critically on the environmental cues available to pathogens and on their reliability for predicting future transmission opportunities. Although motivated by the biology of relapsing malaria parasites, our results provide a general framework for understanding the evolution of dormancy as an adaptive response to periodic environmental fluctuations across diverse pathogen systems.

evolutionary biology↗

bioRxiv2022

Seasonality and the persistence of vector-borne pathogens

Many vector-borne diseases are affected by the seasonality of the environment. Yet, seasonality can act on distinct steps of the life-cycle of the pathogen and it is often difficult to predict the influence of the periodic fluctuations of the environment on the persistence of vector-borne pathogens. Here we analyse a general vector-borne disease model and we account for periodic fluctuations of different components of the pathogens life-cycle. We develop a perturbation analysis framework to obtain useful approximations to evaluate the overall consequences of seasonality on the persistence of pathogens. This analysis reveals when seasonality is expected to increase or to decrease pathogen persistence. We show that seasonality in vector density or in the biting rate of the vector can have opposite effects on persistence and we provide a useful biological explanation for this result based on the covariance between key compartments of the epidemiological model. This framework could be readily extended to explore the influence of seasonality on other components of the life cycle of vector-borne pathogens. Significance statementDoes seasonality increase or decrease the persistence of vector-borne diseases? The devil is in the details and our analysis shows that the effect of seasonality depends on which pathogen traits are affected by seasonality. We highlight the contrasting effects of seasonality in the abundance and/or in the biting rate of the vector on pathogen persistence.

ecology↗