Far East scarlet fever (FESLF) is a severe inflammatory disease that occurs sporadically and in outbreaks in Russia and Japan. The disease is caused Yersinia pseudotubuclosis. There appears to be geographic heterogeneity between virulence factors produced by European and Far Eastern Y pseudotuberculosis strains. Superantigen Y pseudotuberculosis-derived mitogen A (YPMa) triggered by the virulence plasmid pYV is thought to play an essential role in the pathogenesis of FESLF (Amphlett A 2015; Timchenko NF et al. 2016).