Aquatic disease dynamics consist of complex relationships among hosts and pathogens. The study of the determinants of epizootics, their initiation or termination, together with the prediction of the impact of climate change in the ecology and distribution of pathogens require innovative strategies towards the identification of processes, monitoring, and modeling. We developed an ecological model of the Kermack-McKendrick type, sufficiently flexible to study the dynamics of a wide range of marine invertebrate diseases. The model considers a single population of benthic filter feeder organisms consisting of susceptible and infected animals, and infective particles simulating pathogens. It is applicable to diverse host-pathogen systems by means of setting specific initial conditions and parameters such as infection, filtration, mortality and recruitment rates. We evaluate the sensitivity of the model analytically, examining the input parameters and initial conditions in order to answer the questions: What conditions are needed to produce either high infection prevalence or absence of infection? Are there any conditions that cause a significant reduction of prevalence in an infected population? The model performed adequately and proved to be a valuable tool for studying the ecological dynamics of marine host-pathogen systems since it allows an understanding of which factors have the largest influence on model outputs. Moreover, coupling this model to a hydrodynamic model, capable of simulating larval and pathogen dispersion, might be a powerful approach to predict climate-change-driven spatial and temporal evolution of host-pathogen interactions.