O/SEA/Mya-98 lineage foot-and-mouth disease virus was responsible for an extensive epidemic that occurred in late 2018 in Vietnam.

Since late 2018, foot-and-mouth disease (FMD) has reemerged and rapidly swept through pig farms in North and Central Vietnam, despite widespread use of commercial FMD vaccines. To investigate the FMD virus (FMDV) strains responsible for the current epidemics, 40 FMDV samples were collected from 17 provinces during November-December 2018, and the VP1 coding genes were sequenced and analyzed. Phylogenetic analysis and sequence comparisons revealed that all of the reemerging Vietnamese FMDVs belonged to the Mya-98 lineage of the O/Southeast Asia topotype (O/SEA/Mya-98) and shared high nucleotide (99.