Analysis of the presence of Beta-hemolytic streptococci and cytological profiles in horse tracheal lavage samples with diverse clinical respiratory symptoms.
Authors: Pınar Orhan, Çelik Doğan Cansu, Aktaran Bala Deniz, Kumaş Cihan, Mete Alper
Journal: BMC veterinary research
Summary
β-haemolytic streptococci infections impose considerable economic burden on equestrian facilities through cases of strangles and associated respiratory disease, yet the relationship between bacterial presence, airway inflammation, and clinical presentation remains incompletely characterised. Researchers cultured tracheal lavage samples from 133 horses stratified across five groups—asymptomatic controls, those with cough alone, lymph node enlargement alone, combined cough and lymphadenopathy, and animals presenting all three signs (cough, lymphadenopathy, and nasal discharge)—and performed differential cytological analysis to quantify neutrophils, eosinophils, macrophages, lymphocytes, and mast cells within each cohort. The study identified distinct inflammatory cell profiles associated with different clinical presentations and pathogen burden, providing objective data on how airway cytology correlates with the severity and type of respiratory symptomatology observed. These findings offer practitioners a more nuanced understanding of which cytological markers and bacterial isolates carry diagnostic or prognostic significance across the spectrum of streptococcal respiratory disease, potentially informing decisions about sampling, antimicrobial intervention, and prognosis in affected horses. The work underscores the value of tracheal lavage cytology as a quantitative tool—rather than relying solely on clinical signs—to differentiate infection severity and guide management strategies in equine respiratory medicine.
Read the full abstract on PubMed
Practical Takeaways
- •Tracheal lavage cytological analysis combined with bacterial culture can help identify beta-hemolytic streptococcal infections in horses with respiratory signs; use this to confirm strangles diagnosis and guide treatment decisions
- •Understanding the inflammatory cell patterns associated with different respiratory symptoms may help differentiate between beta-hemolytic streptococcal infections and other upper respiratory conditions in your practice
- •Early identification of horses with clinical signs (coughing, lymph node swelling, nasal discharge) through these diagnostic methods enables faster isolation protocols and reduces disease spread in riding clubs and boarding facilities
Key Findings
- •Beta-hemolytic streptococci were isolated from tracheal lavage samples in horses with various respiratory symptoms
- •Cytological profiles including neutrophils, eosinophils, macrophages, lymphocytes, and mast cells were quantified across five clinical symptom groups
- •Correlation between inflammatory cell populations and presence of beta-hemolytic streptococcal species was assessed across symptom severity levels
- •Clinical respiratory symptoms were categorized from asymptomatic controls through single symptoms to multi-symptom presentation including coughing, lymph node swelling, and nasal discharge