Accounting for animal movement improves vaccination strategies against wildlife disease in heterogeneous landscapes

Abstract

Oral baiting is used to deliver vaccines to wildlife to prevent, control, and eliminate infectious diseases. A central challenge is how to spatially distribute baits to maximize encounters by target animal populations, particularly in urban and suburban areas where wildlife such as raccoons (Procyon lotor) are abundant and baits are delivered along roads. Methods from movement ecology that quantify movement and habitat selection could help to optimize baiting strategies by more effectively targeting wildlife populations across space. We developed a spatially explicit, individual‐based model of raccoon movement and oral rabies vaccine seroconversion to examine whether and when baiting strategies that match raccoon movement patterns perform better than currently used baiting strategies in an oral rabies vaccination zone in greater Burlington, Vermont, USA. Habitat selection patterns estimated from locally radio‐collared raccoons were used to parameterize movement simulations. We then used our simulations to estimate raccoon population rabies seroprevalence under currently used baiting strategies (actual baiting) relative to habitat selection‐based baiting strategies (habitat baiting). We conducted simulations on the Burlington landscape and artificial landscapes that varied in heterogeneity relative to Burlington in the proportion and patch size of preferred habitats. We found that the benefits of habitat baiting strongly depended on the magnitude and variability of raccoon habitat selection and the degree of landscape heterogeneity within the baiting area. Habitat baiting improved seroprevalence over actual baiting for raccoons characterized as habitat specialists but not for raccoons that displayed weak habitat selection similar to radiocollared individuals, except when baits were delivered off roads where preferred habitat coverage and complexity was more pronounced. In contrast, in artificial landscapes with either more strongly juxtaposed favored habitats and/or higher proportions of favored habitats, habitat baiting performed better than actual baiting, even when raccoons displayed weak habitat preferences and where baiting was constrained to roads. Our results suggest that habitat selection‐based baiting could increase raccoon population seroprevalence in urban–suburban areas, where practical, given the heterogeneity and availability of preferred habitat types in those areas. Our novel simulation approach provides a flexible framework to test alternative baiting strategies in multiclass landscapes to optimize bait‐distribution strategies.

Assessing the Efficiency of Local Rabies Vaccination Strategies for Raccoons (Procyon Lotor) in an Urban Setting

“…We used a linear mixed-effects model with a logit link to analyze the relative impacts of baiting strategy features on vaccine-based seroprevalence (McClure et al 2022). All covariates were considered as categorical (i.e., "dummy" variables).…”

“…Our framework followed the approaches developed in McClure et al (2022). Code for this framework is available as supporting information in McClure et al (2022).…”

Evaluation of oral baits and distribution methods for Tasmanian devils (Sarcophilus harrisii)†

“…Increasing target uptake could potentially be accomplished through habitat-based and seasonal baiting programs based on devil behavioural and movement ecology, as has been simulated for racoons (McClure et al . 2022).…”

“…Increasing target uptake could potentially be accomplished through habitat-based and seasonal baiting programs based on devil behavioural and movement ecology, as has been simulated for racoons (McClure et al 2022). Likewise, non-target uptake by herbivores and omnivores could potentially be reduced by baiting during periods when other food sources are readily available.…”

Oral Rabies Vaccination of Raccoons (Procyon Lotor) Across a Development Intensity Gradient in Burlington, Vermont, Usa, 2015–2017

“…During August 2015-2017, approximately 24,000 ONRAB vaccine baits (Rosatte et al 2009b) were distributed by hand throughout the study area at a target density of 150 baits/km 2 based on NLCD habitat classifications (McClure et al 2022). Habitats with higher development intensity received fewer baits than areas with lower development intensity because of baiting off-time associated with unbaitable habitat (parking lots, large building footprints, etc.).…”