Abstract
Phylodynamics is a recent field that aims at using genetic sequence data to estimate epidemiological parameters such as the viral population growth rate, the number of infections in the population or even their duration. Its main underlying assumption is that the way viruses spread leaves marks in their genome. In this review, we first introduce the originality of phylodynamics inferences compared to 'classical' phylogenetic approaches. Then, we present the novelty of using phylogenies of infections compared to species trees, while giving some directions to infer of such objects. We discuss the birth of phylodynamics and its first successes, in order to present some of the questions the approach can address. Finally, we highlight some future challenges for the field.