Five-year evidence synthesis of African swine fever in domestic pigs in Southeast Asia: A systematic review and meta-analysis.

Abstract

African swine fever (ASF) continues to threaten pig production systems across Southeast Asia, yet regional epidemiological patterns remain fragmented. This systematic review and meta-analysis synthesized prevalence data to provide a consolidated assessment of ASF burden, spatial distribution, and temporal trends from 2019 to 2023. Following PRISMA 2020 guidelines, a comprehensive literature search was conducted across eight major databases and supplementary sources, with protocol registration in the Open Science Framework. Four reviewers independently screened studies, and eligible publications underwent quality appraisal using the Joanna Briggs Institute (JBI) checklist. Data extraction encompassed prevalence estimates, diagnostic methods, sample types, and geographic information, which were subsequently mapped using QGIS. Meta-analyses, subgroup analyses, meta-regression modelling, and Egger's test were performed in R Studio using the "meta" and "metafor" packages. Twelve studies met inclusion criteria, representing seven Southeast Asian countries. The random-effects model yielded an overall pooled prevalence of 29.14% (95% CI: 20.56-37.72), with substantial heterogeneity (I&#xa0;=&#xa0;100%; &#x3c4;&#xa0;=&#xa0;0.1012). Subgroup analyses demonstrated marked variations by study period, diagnostic method, sample type, and country, with the highest prevalence estimates reported in Vietnam and Lao PDR. Meta-regression identified a significant decline in prevalence over time (p&#xa0;<&#xa0;0.001). Spatial mapping revealed pronounced regional burden prevalence, particularly in the Lao PDR and southern Vietnam. Funnel plot asymmetry and regression testing suggested the presence of small-study effects. These findings underscore the persistent and heterogenous nature of ASF across Southeast Asia, emphasizing the need for harmonized surveillance, strengthened biosecurity in smallholder systems, and enhanced diagnostic capacity.