While the study of multi-strain diseases goes back decades \cite{a1983,Castillo-Chavez1989}, the resulting modelling framework has not yet been generalized to a collection of sub-populations connected through host movement, i.e. a metapopulation (but see \citealt*{Lourenço2013}). Initially introduced through the concepts of island biogeography \cite{h1967}, the network approach of metapopulations can be applied to a variety of systems, including human movement between cities, livestock transport between farms, and wildlife living in fragmented natural habitats. In each case, there exist relatively high-density areas which are connected to one another through a network of individuals' movement. A metapopulation framework allows the application of network analyses to characterize patterns of connection within the larger system, and can provide unique insights across scales.