Understanding Mild-Moderate Equine Asthma: What the Research Tells Us

If you’ve ever been involved in caring for horses, you know that respiratory health is a major focus. One term that’s becoming more recognized is mild-moderate equine asthma (mEA), previously known as inflammatory airway disease. This form of asthma affects a significant number of horses and can impact their well-being and performance. So, what do we know about diagnosing and understanding it? A recent review aimed to answer just that by evaluating the evidence supporting the current definition.

What Is Mild-Moderate Equine Asthma?

mEA is part of a spectrum of respiratory conditions in horses, differing from severe forms like recurrent airway obstruction (or "heaves"). It doesn't involve increased breathing difficulty at rest but is marked by signs like coughing, poor performance, and specific inflammatory changes in the airways.

The Core of the Review

Researchers set out to assess the quality of evidence backing the diagnostic criteria for mEA. They analyzed 45 studies, covering data from over 6,000 horses worldwide. These studies were mostly observational and varied greatly in how they were conducted, which posed challenges in drawing universal conclusions.

Key Findings

• Cough and Mucus: There was consistent evidence linking coughing and increased tracheobronchial mucus.
• Cough and Cell Analysis (BAL Cytology): Associations were found between coughing and certain cell types in the bronchoalveolar lavage (BAL), a procedure that collects fluid from the lungs to check for inflammation.
• Performance Issues: Diagnosing mEA based on performance was more complex, often reliant on subjective measures such as trainer opinions.
• Lung Function: Evidence linking BAL results or mucus with lung function was inconsistent, suggesting more research is needed to confirm these relationships.

Challenges Highlighted 

The review noted significant variability in how studies defined and measured mEA indicators. This lack of standardization made it difficult to conduct meta-analyses and draw broader conclusions. Additionally, many studies faced limitations like small sample sizes and potential biases due to non-randomized methods.

Why This Matters

The study underscores the need for standard practices in diagnosing and reporting on mEA. Such consistency would not only help veterinarians in making more reliable diagnoses but also aid in future research that could improve treatments and outcomes for horses.

Final Thoughts

Understanding mild-moderate equine asthma is still evolving. This review provides a foundation for future studies to build on and points to the importance of standardized methods. As horse owners and caretakers, staying informed about advances in veterinary medicine helps ensure our equine companions receive the best possible care.