Sherburne, S. | bioRxiv Science

bioRxiv2024

Comparing efficiencies of population control methods for responding to foreign animal disease threats in wild pigs

Introductions of foreign animal diseases (FADs) into free-ranging wildlife can be difficult to control and devastating for domestic livestock trade. Combating a new FAD introduction in wildlife with an emergency response requires quickly limiting spread of the disease by intensely removing wild animals and recovering their carcasses for proper disposal. In the case of African swine fever virus (ASFv) in wild pigs (Sus scrofa), which has been spreading in many regions of the world, there is little information on the time- and cost-efficiency of methods for intensively and consistently removing wild pigs and recovering carcasses in an emergency response scenario. We compared the efficiencies of aerial operations, trapping, an experimental toxic bait, and ground shooting in northcentral Texas, USA during two months in 2023. Removing and recovering carcasses of wild pigs averaged a rate of 0.15 wild pigs/person hour and cost an average of $233.04/wild pig ($USD 2023) across all four methods. Aerial operations required the greatest initial investment but subsequently was the most time- and cost-efficient, costing an average of $7,266 to incrementally reduce the population by 10% including recovering carcasses. Aerial operations required a ground crew of [~]7 people/helicopter to recover carcasses. Costs for reducing the population of wild pigs using trapping were similar, although took 13.5 times longer to accomplish. A benefit of trapping was carcass recovery was incorporated. Toxic baiting was less efficient because carcass recovery required substantial time, and we removed very few wild pigs with ground shooting in this landscape. We recommend combining aerial and trapping methodologies to remove wild pigs and their carcasses efficiently and effectively during a FAD response. Overall, our findings can inform the preparation of resources, personnel needs, and deployment readiness for FAD responses involving wild pigs.

ecology↗

bioRxiv2024

Operational lessons learned from simulating an elimination response to a transboundary animal disease in wild animals

Transboundary animal disease (TAD) introductions can have myriad economic, ecological, and societal impacts. When TADs are introduced into wild species, rapid and intense control efforts to reduce wild animal host populations are sometimes needed to eliminate the disease and prevent endemicity and spillover to domestic animal populations. Yet, such intensive efforts are non-trivial, and the rarity of TAD introductions means that personnel rarely have direct experience with these types of operations. Thus, explicit assessments of operational challenges for these kinds of efforts can provide direction to build emergency response preparedness capacity. Here, we simulated a TAD control effort in response to initial detection of a hypothetical index case of a TAD in wild pigs (Sus scrofa) (e.g., African swine fever; ASF). We used three removal methods (aerial control, trapping, and an experimental toxic bait). Then, we conducted an after-action assessment to identify operational challenges for rapidly reducing a population of invasive wild pigs within a simulated outbreak zone. We also simulated carcass recoveries of dispatched pigs, similar to what might be conducted during a response to a TAD with carcass-based transmission (e.g., ASF virus). Here, we describe operational challenges identified during our effort, alongside technological development solutions and a priori strategy needs to improve TAD response operation outcomes.

ecology↗