Epidemiology of recent outbreaks of Foot-and-mouth-disease in cattle and emergence of SEA/Mya-98 topotype in Bangladesh

Background Foot-and-Mouth Disease (FMD) remains a major transboundary threat to livestock production and food security in Bangladesh. This study investigated the epidemiological characteristics and genetic diversity of FMD virus (FMDV) associated with two outbreaks affecting 24 cattle farms in Bogura and Mymensingh districts during June, and September and October 2024, respectively. Methods Epidemiological data and clinical samples were collected, and FMDV was confirmed and serotyped using quantitative RT-PCR. Whole-genome sequencing was performed on the Ion Torrent PGM platform, and sequence analyses were conducted using MEGA12 and BioEdit software. Results Epidemic curve analysis classified both outbreaks as propagated. The introduction of newly purchased cattle into the herd without prior quarantine was identified as the likely source of infection. FMDV serotype O was detected in both outbreaks. The overall attack risk and case fatality were 65.8% and 33.3%, respectively. Phylogenetic analysis revealed the emergence of a previously unreported topotype, SEA/Mya-98, in Bangladesh. Compared with the current vaccine strain (O/India/R2/75), 22 and 9 amino acid substitutions were identified in the VP1 region of Ban/Myn3/2024 and Ban/Bog4/2024 isolates, respectively. Conclusions These findings underscore the importance of improved biosecurity prior to herd introduction, strengthened cross-border trade regulation, rapid outbreak response, and sustained molecular surveillance.