Case definition
Based on the previous consensus statement,1 a diagnosis of mild-moderate asthma (MA) was made based on the presence of clinical signs (poor performance, chronic occasional coughing, or both), evidence of airway inflammation in BALF cytology, presence of significant amount of tracheal mucus detected by endoscopy (grade > 2/5), and the exclusion of severe asthma (SA) based on history and clinical signs. For BALF cytology, the ‘less restrictive’ cut-off was used: neutrophils > 10%, mast cells > 5% and eosinophils > 5% in individual (left and right) BALF,1,19 and neutrophils > 9%, mast cells > 3% and eosinophils > 3% in pooled BALF.20 A diagnosis of SA was made based on history, presence of increased respiratory effort at rest, and moderate to severe neutrophilia in BALF (> 25%) in horses of middle to advanced age (> 7 years old).1 Horses without coughing, nasal discharge, or increased respiratory effort, with normal BALF cytology from both lungs, and with a negative bacterial culture from TW were classified as controls (CTL). Cytology was classified as positive when at least one fungal element (spore, hyphae) was observed on the slide (TW, individual or pooled BALF). Fungal culture was classified as positive when one or more colonies were observed (and identified) in a sample (TW or pooled BALF).