Quantifying ASF Outbreak Dynamics in the Philippines (2019–2023) Using Joinpoint Regression and the Estimated Dissemination Ratio
Simple Summary African swine fever (ASF) continues to pose a serious challenge to pig production in the Philippines. This study provides a comprehensive characterization of ASF epidemic dynamics and examines how ASF spread over time and across regions using national laboratory-confirmed surveillance data and complementary temporal analytical methods. The results showed that outbreaks expanded rapidly after 2019, reached a peak in September 2020, and were followed by smaller but recurring waves until 2023. Disease occurrence varied across regions, with earlier activity observed in Luzon and later outbreaks reported in the Visayas and Mindanao. ASF cases were more frequently detected during the later months of the year, particularly from September to November. Over time, the pattern of transmission appeared to shift from large, synchronized outbreaks to smaller, more localized and persistent disease activity. These findings highlight the importance of continuous surveillance, timely outbreak investigation, and adaptable control strategies to support ASF prevention and control in the Philippines.