Optimal vaccination strategies against vector-borne diseases

Area of Science:

• Veterinary Epidemiology
• Infectious Disease Modeling
• Arthropod-borne Diseases

Background:

• Bluetongue virus (BTV) poses a significant threat to cattle populations.
• Culicoides biting midges are the primary vectors for BTV transmission.
• Understanding transmission dynamics is crucial for effective disease control.

Purpose of the Study:

• To evaluate the efficacy and cost-effectiveness of eight preventive vaccination strategies for Bluetongue virus in Denmark.
• To determine optimal vaccination cover and minimum costs under various scenarios.
• To assess the impact of different grazing conditions and index case locations on disease spread.

Main Methods:

• A process-oriented, semi-agent-based model was developed to simulate BTV spread by Culicoides midges.
• The model incorporated passive and active midge flight, seasonal midge abundance, and temperature-dependent biological processes.
• Eight vaccination strategies were tested across four grazing conditions and three index location scenarios.

Main Results:

• Vaccinating cattle on pasture was the most economical approach for medium-risk profiles (under 1000 affected cattle).
• Regional vaccination strategies showed improved outcomes when index cases were located within vaccinated zones.
• The long-range transmission capabilities of midge-borne diseases remain a significant factor influencing strategy effectiveness.

Conclusions:

• Pasture-based vaccination offers a cost-effective solution for localized Bluetongue virus control.
• National vaccination schemes are recommended for greater robustness against unpredictable long-range disease spread.
• Further research is needed to better quantify the long-range transmission dynamics of vector-borne diseases.