Identification of a novel genotype of streptococcus equi subspecies equi in a donkey suffering from strangles

Abstract

Strangles is a contagious bacterial disease of equines and is prevalent worldwide. Host-restricted Streptococcus equi subspecies equi is the etiology. In April 2019, strangles was diagnosed in a donkey in the quarantine area of an intensive donkey farm. The infection was confirmed by clinical signs, bacterial isolation, histochemistry, PCR and sequencing. Based on the M-protein typing method, analysis of SeM sequencing data indicated that the isolated S. equi strain CN190402 belongs to a novel genotype SeM-138. The present study increases knowledge of the molecular epidemiology of S. equi and will lead to a greater understanding of the diversity of this pathogen. Meanwhile, it emphasized the necessity of quarantine areas and the importance of biosecurity for intensive donkey farms to prevent future outbreaks.