The Effect of Partial and Temporary Vaccination on African Swine Fever Eradication Rates

Area of Science:

• Veterinary Epidemiology
• Wildlife Disease Ecology
• Mathematical Modeling

Background:

• African swine fever (ASF) poses a severe threat to the pig industry, with wild boar acting as a key epidemiological reservoir.
• Currently, no fully effective and safe ASF vaccine exists, and future vaccines are expected to have limitations in efficacy and duration.

Purpose of the Study:

• To model the impact of a potential ASF vaccination campaign on wild boar populations.
• To evaluate the influence of vaccine efficacy, protection duration, and vaccination effort on ASF eradication probabilities.
• To assess the interaction of partial vaccination with other ecological and management factors affecting ASF persistence.

Main Methods:

• Development of an individual-based, spatially explicit model simulating wild boar demography and ASF epidemiology.
• Simulation of vaccination campaigns with varying parameters: number of vaccinated animals, vaccine efficacy, and duration of protection.
• Analysis of eradication probabilities and the interplay of vaccination with factors like population density and carcass removal.

Main Results:

• High-efficacy, short-duration vaccines showed low eradication chances, requiring high vaccination effort (2.5/km²).
• Low-efficacy, long-duration vaccines were ineffective, failing to achieve acceptable eradication rates in simulations.
• Vaccination alone is insufficient for ASF genotype II eradication; integration with hunting and carcass removal is necessary.

Conclusions:

• Vaccination against ASF genotype II in wild boar is not a standalone solution for eradication.
• A comprehensive strategy integrating vaccination with population density control (hunting) and carcass removal is essential.
• Optimal vaccination timing depends on vaccine duration: annual or biannual distribution for long-duration vaccines, single end-of-winter distribution for short-duration vaccines.