Epidemiological update on spatial and space-time clusters of African swine fever in the Philippines

African swine fever (ASF), particularly the highly contagious Genotype II strain, is a transboundary viral disease causing up to 100% mortality in swine and threatening food security across the Asia-Pacific region. Since 2019, control strategies in the Philippines have relied on depopulation and strict administrative zoning to limit contiguous, land-based spread. However, the long-term effectiveness of these approaches within the country's fragmented archipelagic landscape remains poorly understood, complicating evidence-based resource allocation and preparedness for regional vaccination campaigns. Here we show that the endemic trajectory of ASF was highly non-uniform across the three main island groups of the Philippines from October 2022 to October 2024. Spatiotemporal analysis of a national surveillance dataset comprising 8,213 barangay-level events revealed twelve statistically significant retrospective space-time clusters-with radii up to 183.2 kilometers-and highly asynchronous regional epidemic waves across Luzon, the Visayas, and Mindanao. Although crude case volumes were highest in Luzon (52.10%), followed by the Visayas (31.69%) and Mindanao (16.21%), accounting for swine population density reshaped the spatial distribution. Spatial mapping and a Getis-Ord Gi* hotspot analysis consistently identified the highest burden of reported ASF events within Regions IV-A, IV-B, and VI, specifically peaking on Mindoro Island and in the Western Visayas. Together, these findings demonstrate that maritime borders fail to provide natural biosecurity isolation against transboundary viral transmission. Consequently, region-specific interventions and resources must be dynamically allocated to address this heterogeneous spatial burden. These spatiotemporal results provide the evidence-based framework necessary to transition toward targeted sub-national surveillance and to systematically evaluate the epidemiological impact and guide live-attenuated vaccine implementation in the Philippines and analogous archipelagic settings throughout the Asia-Pacific.