Predicting Suitable Areas for African Swine Fever Outbreaks in Wild Boars in South Korea and Their Implications for Managing High-Risk Pig Farms

Abstract

African swine fever (ASF) is a highly contagious disease affecting domestic pigs and wild boars, with no effective vaccine or treatment available. In South Korea, extensive measures have been implemented to prevent ASF transmission between wild boars and ASF spillover from wild boars to pig farm sectors, including the search for ASF-infected carcasses in mountainous forests and the installation of fences across wide areas of these forests. To determine the priority search range for infected carcasses and establish pig farm-centered quarantine measures, it is necessary to predict the specific path of ASF outbreaks in wild boars and identify pig farms at high risk of ASF spillover from wild boars. Here, we aimed to predict suitable areas and geographical paths for ASF outbreaks in wild boars using the MaxEnt model and shortest-path betweenness centrality analysis. The analysis identified a high frequency of ASF outbreaks in areas with a suitability value ≥0.4 on the suitability map and in areas within a 1.8 km range from the path on the shortest-path map, indicating these areas were high-risk zones for ASF outbreaks. Among the 5063 pig farms analyzed, 37 were in the high-risk zone on the suitability map, 499 were in the high-risk zone on the shortest-path map, and 9 were in both risk zones. Of the 51 pig farm sectors with a dense distribution of pig farms (kernel density ≥ 8), 25 sectors were in contact with or partially overlapped the high risk zone on the suitability map, 18 sectors were located within the high risk zone on the shortest-path map, and 14 sectors were located within both risk zones. These findings aided in determining the priority range for searches for wild boar carcasses and enabled the establishment of preemptive ASF prevention measures around the pig farming sectors that are at risk of ASF spillover from wild boars.

Predicting Disparity between ASF-Managed Areas and Wild Boar Habitats: A Case of South Korea

“…This indicates that wild boars prefer dense forests as core habitats, whereas ASF management cannot be implemented in some regions in dense forests near urban areas. Although ASF management has been implemented in extensive wild boar habitats of South Korea, some minor regions with dense forests have a high risk of ASF transmission [16,63,64].…”

“…ASF outbreaks have occurred in China, Vietnam, India, Indonesia, Philippines, North Korea, and South Korea. To prevent further spread of ASF, culling (or hunting) of wild boars has been conducted in many countries, leading to a decrease in pork production, an increase in the price of pork-based goods, and vulnerability of regions where pork is a staple food [16][17][18]. Understanding and managing the spread of ASF is vital for sustaining local and global economics, food security, biosecurity, and the environment.…”

“…Many previous ASF studies have applied SDMs to predict wild boar habitats to support the management of ASF spread [16,30,[34][35][36]. Choi et al (2023) [16] estimated the shortest paths for an ASF outbreak by using MaxEnt and network analysis.…”

“…Many previous ASF studies have applied SDMs to predict wild boar habitats to support the management of ASF spread [16,30,[34][35][36]. Choi et al (2023) [16] estimated the shortest paths for an ASF outbreak by using MaxEnt and network analysis. Bergmann et al (2021) [37] estimated wild boar habitats in the European continent and applied them to determine the areas for installing barriers that prevent wild boar movement.…”

Spatiotemporal pattern and suitable areas analysis of equine influenza in global scale (2005–2022)

“…Their findings were instrumental in implementing targeted prevention and control strategies. Similarly, Choi et al utilized the Maxent model to accurately predict suitable areas for African swine fever (ASF) outbreaks in wild boars in South Korea ( 15 ). Their findings established preemptive measures to prevent ASF in pig farming sectors at risk of ASF spillover from wild boars.…”