Evolutionary dynamics of dengue virus populations within the mosquito vector

• Dengue viruses exist as heterogeneous populations of related genetic variants.
• Dengue virus populations evolve during the course of a single infection.
• Deep-sequencing approaches allow monitoring of within-host evolutionary dynamics.
• Within-host processes can be inferred from within-host evolutionary dynamics.
• Within-host and epidemiological dynamics of dengue viruses are interrelated.

To date, dengue virus evolution has mainly been addressed by studies conducted at the between-host level. Like other pathogens with high mutation rate and rapid replication, dengue viruses also evolve during the course of an infection. Over the last few years, the advent of deep-sequencing technologies has facilitated studies of dengue virus populations at the within-host level. Here, we review recent advances on the evolutionary dynamics of dengue virus populations within their mosquito vector. We discuss how identifying the evolutionary forces acting on dengue virus populations within the mosquito can shed light on the processes underlying vector–virus interactions and the evolution of epidemiologically relevant traits.