A unifying framework for the transient parasite dynamics of migratory hosts

Significance When animals migrate, they take their parasites with them—or not. Understanding infectious disease in migratory animals is challenging because the vast distances covered result in variable host densities and infection pressure and make it difficult to collect data. Empirical studies show that migrants may have higher, lower, or the same infection intensity as residents. We present a model that produces different infection patterns and migration outcomes under different parameters, laying a theoretical foundation for exploring what may be driving observed diverse patterns in nature. Our model can help guide empirical studies, suggesting when and where data need to be collected in order to distinguish mechanisms, and inform targeted management and conservation efforts.