BACKGROUND

Strangles is a highly contagious equine respiratory disease caused by . It is a globally significant pathogen and one of the most common infectious agents in horses. In Iraq, no sequencing data on this pathogen are available, and only two molecular studies have been published to date. This study provides preliminary insights into strain diversity and provides a foundation for future large-scale investigations.

AIM

This study aimed to investigate the molecular characteristics, identify gene alleles, and perform a phylogenetic analysis of isolates from horses in Baghdad, Iraq.

METHODS

We analyzed 59 . isolates previously obtained from horses clinical samples. Conventional PCR (Polymerase Chain Reaction) targeting the gene was used to identify . Additionally, nine PCR- positive gene products were sequenced, followed by phylogenetic analysis and allele identification.

RESULTS

We confirmed 49 isolates as from the 59 isolates according to the molecular assay. Additionally, nine PCR products were used for sequencing and allele typing of the gene, which provided the initial report of -97 allele identification in Iraq. Phylogenetic analysis along with gene typing revealed a close relationship between the Iraqi strains and one Iranian strain with 100% sequence identity, revealing important epidemiological relationships that may indicate regional ties to the strain detected in Iran.

CONCLUSION

The present study represents the first investigation of allele typing in Iraq, identifying the -97 allele of along with its unique amino acid variations. The findings highlight genetic similarities between Iraqi isolates and a strain from Iran, suggesting the potential regional dissemination of .