Clinical, Bacteriological, and Molecular Study of Streptococcus equi Isolated from Horses in Baghdad, Iraq

This study addresses the limited research on Streptococcus equi subsp. equi (S. equi) infections in horses in Baghdad, Iraq, a highly contagious disease known as strangles. The objective was to investigate the clinical, bacteriological, and molecular characteristics of these infections. A total of 115 samples were collected from 100 racehorses, consisting of 85 nasal swabs from horses without abscesses and 30 samples (15 nasal swabs and 15 abscess samples) from 15 horses with abscesses. The bacterium was identified based on traditional bacteriological diagnostic methods and confirmed using PCR amplification of the seeI gene. PCR detected a 34% infection rate. The findings demonstrated the PCR was more sensitive than bacterial cultivation in relation to the diagnosis of strangles. Clinical signs included fever, dyspnea, mucopurulent nasal discharge, submandibular lymph node abscessation, dysphagia, and significant respiratory distress. This study concluded that strangles significantly impact equine health, manifesting in moderate to severe clinical signs that can lead to mortality in affected horses. This underscores the necessity of studying the causative agent, S. equi, through advanced genetic methodologies to achieve accurate diagnosis and facilitate comprehensive epidemiological research. Furthermore, investigating the seeI gene expressed by S. equi is crucial to understanding its role in the disease process and developing effective control measures‎‎‎.