Detection of spatiotemporal variation in Ranavirus distribution using eDNA

Amphibian population declines have been associated with emerging diseases including ranaviruses, which can cause mass die-offs across entire amphibian communities. Understanding and mitigating disease spread requires knowledge of spatial and temporal patterns of pathogen distribution, but also how environmental factors influence pathogen occurrence. We applied environmental DNA (eDNA) detection tools to survey spatial and temporal distributions of ranaviruses by sampling 103 waterbodies in southeastern Ontario, Canada, and assessed the role of abiotic factors as predictors of pathogen occurrence. Ten waterbodies sampled during June-August (>30 km between sites) revealed that ranavirus was marginally more prevalent (p = 0.055) during the latter part of the summer. Ninety-three sites sampled at a finer scale (<10km between sites) exhibited seasonal variability in ranavirus detection (site prevalence: 56% May; 66% July). Occupancy modeling revealed that wetland size and elevation inf...