Heterogeneous shedding and susceptibility in a Caenorhabditis elegans transmission model

Abstract

Variation in transmission plays a crucial role in shaping the dynamics of infectious diseases. Population heterogeneity is known to contribute to this variation and is often represented in epidemiological models. However, it is not always clear a priori what sources of variation should contribute meaningfully to a given scenario, and it can be challenging to infer distributions of underlying processes from data. In this study, we demonstrate the use of Caenorhabditis elegans as a tractable system in which high-quality data can be produced for experimental epidemics. We show that distributions of shedding and susceptibility in this host can be experimentally decoupled to measure heterogeneity in transmission processes. We observe and quantify super-shedding and heterogeneous susceptibility, and we show that distributions of population heterogeneity and transmission outcomes have features conserved with real-world epidemics. Our results quantify sources of heterogeneity in bacterial transmission in this small model organism and establish C. elegans as a promising quantitative model for experimental epidemics.