Evolutionary and Spatiotemporal Dynamics of Foot-and-Mouth Disease Virus in Ethiopia (1957-2025): A Molecular Perspective on Serotype Persistence and Emergence.

Foot-and-mouth disease (FMD) represents a significant global economic burden and remains the primary constraint on Ethiopia's livestock economy and international trade. This desk review synthesized 60 years of data (1957-2025) using a structured, multidatabase search across four domains: disease, genotype/lineage, geographic spread, and temporal context. Data were stratified into three periods: Period I (1957-1980), Period II (1981-2000), and Period III (2001-2025). Results indicate that Period I saw the identification of serotypes O, A, and C, though serotype C has not been detected after 1983. Period II was marked by the continued circulation of serotypes O and A, and the first emergence of Serotype SAT 2 near the Kenya-Ethiopia border, which temporarily disappeared until its major re-emergence in 2007. Period III is characterized by a significant intensification and modernization of FMD virus (FMDV) outbreak investigation that provided more granular data on viral activity in the country. The period saw four major endemic serotypes O, A, SAT 2, and SAT 1, SAT one being confirmed for the first time during this period, circulate simultaneously and covering the entire country. Molecular analyses revealed a heterogeneous landscape: serotype O is dominated the serotype distribution in the country by its O/EA-3 and O/EA-4 topotypes, while serotype A involving complex lineages (Africa G-I, G-IV, and G-VII) follows in serotype O and precedes serotype SAT 2 in distribution. Notably, serotype SAT 2 has historically comprised four topotypes (IV, VII, XIII, and XIV), with the recent dominance of the re-emergent SAT 2/XIV topotype. The global biosecurity threat posed by FMDV SAT 2 topotype XIV stems from its unprecedented transcontinental dissemination into immunologically naive regions, rather than inherent lethality. This expansion highlights the complex evolutionary dynamics of the virus and the vulnerability of current surveillance system. The global dissemination of emerging lineages, such as SAT 2 topotype XIV, underscores the complex evolutionary dynamics and environmental plasticity inherent across all FMDV serotypes. The rapid shift of these viruses into nonendemic territories highlights critical vulnerabilities in existing biosecurity. Ultimately, these dynamics necessitate a shift toward adaptive, multiserotype surveillance and integrated control frameworks to address the continuous antigenic evolution and geographical expansion of the virus. Advancing Ethiopia along the progressive control pathway (PCP-FMD) is critically contingent upon evaluating the protective efficacy of current trivalent vaccines against rapidly evolving field strains. Immediate intervention is required to address diverged genotypes that jeopardize both national herd health and international market access.