2025 Theses Doctoral

Heterogeneity Across Scales: Linking Movement, Contact, and Landscape to Canine Distemper Virus Transmission in New York City Raccoons

Plimpton, Laura Dudley

Urbanization alters wildlife behavior, movement, and contact structure, reshaping the ecological processes that underpin pathogen transmission and persistence. Using raccoons (Procyon lotor) and Canine Distemper Virus (CDV; Morbillivirus canis) as a model system, this dissertation integrates movement ecology, spatial modeling, and genomic epidemiology to evaluate how heterogeneity across scales of transmission mediates pathogen circulation and persistence within New York City’s urban landscape.

At the individual scale (Chapter 1), hidden Markov models applied to fine-scale GPS data revealed that raccoon movement responds predictably to the cadence of urban residential trash availability, with increased exploratory and encamped behaviors on trash nights indicative of temporally cued foraging.

At the dyadic scale (Chapter 2), resource-selection analyses of high-resolution co-occurrence data showed that raccoons were more likely to come into contact near specific resources, with the strongest effect observed for anthropogenic resources. Multivariate analyses identified distinct contact typologies including prolonged male-male encounters near human subsidies, female-female interactions at natural features, and transient male-female encounters, demonstrating that sex and resource distribution jointly structure contact heterogeneity.

To assess how these behavioral patterns influence realized transmission (Chapter 3), whole genome CDV sequences from a local (within-patch) outbreak were used to reconstruct transmission networks (“who infected whom”). Transmission chains were male-biased and spatially localized, with spread centered around resource-rich, urban edges. Stochastic epidemic simulations demonstrated that incorporating trait-based (raccoon sex) structure prolonged and amplified outbreaks, emphasizing how within-patch dynamics regulate local epidemic trajectories.

Scaling to the city level (Chapter 4), continuous phylogeographic reconstruction of CDV dispersal using whole viral genomes collected during a 2022-2024 epizootic showed metapopulation-like spread, characterized by localized amplifications in subpopulations connected by infrequent natural dispersal or human-mediated movements. Collectively, these findings demonstrate how behavioral and spatial heterogeneity interact to propagate local transmission events into persistent, citywide circulation.