Study population
Among the 174 horses sampled, 3 horses were excluded because samples
were uninterpretable on reception at the laboratory, and 16 were
excluded from the study because of respiratory issues unrelated to
equine asthma: 10 with infectious pneumonia, 5 with exercise-induced
pulmonary haemorrhage (EIPH) and 1 with interstitial pneumonia. Overall,
155 horses were included. The population was composed of 85 Standardbred
racehorses (54.8%), 20 sport horses (12.9%), and 50 leisure horses
(32.3%). Horses were aged from 2 to 25 years (median 6 years), with a
total of 38 entire males (24%), 60 geldings (39%) and 57 females
(37%).
Of these, 85 horses were diagnosed with MA, 35 horses were SA and 35
horses were considered controls (CTL). Amongst the MA group, 29.4%
(25/85) exhibited mast cell inflammation only, 2.4% (2/85) eosinophilic
inflammation only, 43.5% (37/85) neutrophilic inflammation only, 11.8%
(10/85) increased tracheal mucus score only and 12.9% (11/85) had a
mixed pattern amongst the four inclusion criteria. All horses had a TBS
of 0.