Spatiotemporal modeling of parasite aggregation among fish hosts in a lentic ecosystem

Parasite aggregation is a frequently occurring phenomenon where majority of the parasites accumulate in the smaller fraction of the host population while many individual hosts have low parasite load. One of the mechanisms of parasite aggregation is heterogeneity in the host-parasite interaction. Here, we aim to develop and analyze a spatiotemporal model to explain the details of this mechanism. We construct an agent-based simulation involving fish hosts that forage on zooplanktons harboring macroparasites. In this study, we restrict our simulations to a lentic ecosystem, i.e., still, closed freshwater environment. Our simulations show that (i) the initial sizes of the population of both the fish and zooplanktons have minimal effect on the aggregation of parasites; (ii) increasing the probabilities of reproduction of both fish and zooplankton lead to parasite aggregation among fish hosts; and (iii) aggregation occurs either by decreasing the size of the infection area or increasing the size of the zooplankton-free area in the lentic ecosystem. Our results can be used to provide insights and visualization of the underlying processes leading to aggregation. These can also be used to aid experimentalists in determining the statistical distribution of parasites in hosts for disease prevention and control.