Cytology profile and age influence in the equine bronchoalveolar lavage in healthy and asymptomatic inflammatory airway disease

Abstract

Pulmonary inflammatory diseases have been observed in equine since their domestication. Non-infectious disease processes of the lower airways are amongst the most important diseases of the equine respiratory tract. This study aims to determine the cytology profile and effect of age on the evaluation of equine bronchoalveolar lavage (BAL) obtained from healthy animals and from horses with asymptomatic inflammatory airway disease (IAD). Thirty two horses, including 20 males and 12 females, without clinical signs of pulmonary disease and with age varying from 4 to 21 years, were assigned to two groups: 15 animals in the control group and 17 in the asymptomatic group. Groups were divided according to physical examination and mucous accumulation observed during tracheal endoscopy. The BAL results from healthy and asymptomatic horses were, respectively: 56.9% and 48.0% macrophages, 37.2% and 40.0% lymphocytes, 3.3% and 7.1% neutrophils, 1.7% and 1.4% mast cells, 0.3% and 0.7% eosinophils; 0,5% and 0.4% epithelial cells. When horses in the two groups were analyzed according to their age range, no differences were found. In conclusion, IAD in the asymptomatic group was significantly different from the control group. The asymptomatic horses presented a discrete infiltrate of neutrophils, which does not influence cytological evaluation of BAL.