Renibacterium salmoninarum (Rs) is the causative agent of bacterial kidney disease (BKD), a significant disease of Chinook salmon in the Great Lakes. Rs can cause a long-term persistent infection and infected fish may not necessarily show disease. The standard susceptible-infected-recovered (SIR) population framework for disease does not model Rs infection dynamics well. Fenichel et al. 2009 (Ecol. Apps V19:747) proposed a conceptual framework for Rs, which we have modified here as the ‘susceptible-latent-diseased-latent’ (SLDL) model.