A spatial model to forecast raccoon rabies emergence

Area of Science:

• Veterinary epidemiology
• Disease ecology
• Spatial risk modeling

Background:

• Raccoon rabies variant is enzootic in eastern US, causing over 60% of annual animal rabies cases.
• Oral rabies vaccination (ORV) programs aim to prevent further spread.
• The susceptibility of rabies-free areas to outbreaks remains poorly understood.

Purpose of the Study:

• To evaluate a spatial risk model for forecasting raccoon rabies spread.
• To assess the susceptibility of both rabies-free and enzootic areas.
• To compare model predictions with historical surveillance data.

Main Methods:

• A Poisson Regression Model, adapted from New York State studies, was used.
• Demographic, environmental, and geographical data from Ohio, West Virginia, and Pennsylvania were incorporated.
• Susceptibility was estimated at the census tract level.

Main Results:

• Approximately 70% of the disease-free region exhibited moderate to very high susceptibility to raccoon rabies.
• Only 23% of the enzootic region showed similar susceptibility levels.
• High susceptibility areas were identified west of current ORV intervention zones, particularly in southern Ohio and western West Virginia.

Conclusions:

• The spatial risk model accurately predicted areas of high raccoon rabies susceptibility, aligning with historical data.
• Significant portions of disease-free regions pose a considerable risk for rabies emergence.
• Findings can inform and enhance the efficiency of raccoon rabies control interventions.