A visual representation of the steps we outline in this review as part of a systems biology approach to infectious disease from discovery to representation to application. Arrows highlight the iterative and interconnected nature of systems biology as a process. CRISPRa, CRISPR activation; CRISPRi, CRISPR inhibition; E-MAP; epistatic mini-array profile; GWAS, genome-wide association studies; RNAi, RNA interference; seq, sequencing.