Rapid diagnosis of strangles (Streptococcus equi subspecies equi) using PCR.

The research paper discusses the use of Polymerase Chain Reaction (PCR) assays for the rapid diagnosis of Strangles, a common equine infectious disease caused by Streptococcus equi subspecies equi.

Streptococcus Equi and Strangles Disease

• The primary subject of the study is Strangles, one of the most prevalent infectious diseases affecting equines globally. It presents serious health, welfare, and socio-economic challenges. The disease can be hard to detect, often resulting in rapid spread and underestimation of its prevalence.
• Strangles is caused by the bacterium Streptococcus equi subspecies equi (S. equi), detection of which can be challenging.
• The disease can linger in carriers for an extended period, posing ongoing transmission risks and hindering efforts to control outbreaks.

Need for Better Diagnostic Methods

• The classical method of diagnosing Strangles is via microbiology, a process that can misrepresent the actual prevalence of the disease due to its slow-paced nature.
• The research underscores the urgent need for rapid, cost-effective diagnostic tests to help manage and control this infectious disease more effectively.

Introduction of Multiplex PCR Assays

• In response to this need, two multiplex assays were developed and validated for the detection of S. equi and S. equi subspecies zooepidemicus, the latter being another common equine pathogen often confused with S. equi.
• The new assays (tests) were validated using 59 strains of S. equi and 59 strains of S. zooepidemicus, collected from different geographical areas.
• The PCR tests demonstrated a specificity of 98% and a sensitivity of 95%, indicating high reliability in differentiating between the two subspecies and accurately detecting their presence.

Implications and Advantages of the New Assays

• The assays can be performed directly from clinical swabs, an aspect that further boosts the ease and speed of diagnosis.
• The developed assays offer a reliable, quick, and economical solution for diagnosing Strangles, thus holding potential for improved disease management and control.