Equine Pasture Asthma in Brazil

ABSTRACT

Background: Summer Pasture Associated Obstructive Pulmonary Disease (SPAOPD), or Equine Pasture Asthma (EPA),has been described as an environmentally-induced respiratory disease that occurs during the warmer and more humidmonths, leading to reversible airway obstruction, persistent and non-specific airway hyper-responsiveness, and chronicneutrophilic airway inflammation. Exacerbation of clinical signs vary according to warm seasons and range from mildto severe episodes of wheezing, coughing, and laboured breathing, being highly debilitating to the equine. This reportdescribed two cases of Equine Pasture Asthma that showed clinical and environmental similarities with Summer PastureAssociated Obstructive Pulmonary Disease.Cases The patients were crossbreed geldings that have never been stabled and were used for cattle management in a farmin southeastern Brazil. They presented poor performance and a persistent cough for over 3 years. Initially, the respiratorysigns were only observed after exercise but, over the years, it gradually progressed to being observed when the horses wereat rest. Both animals had a history of regular deworming and were previously treated by other veterinarians with antibiotics,clenbuterol, and mucokinetics. Little improvement was noticed by the owner and the signs returned over time as treatmentwas often discontinued. Clinical findings were compatible with the grade 3 mucus classification as well as with score 2for Severe Asthma. BALF cytology was done according to routine procedure. Animal 1 presented slides with free yeast,macrophages, and mucus with Curschmann’s spiral and counting of 29.7% of neutrophils (NE), 43.7% of lymphocytes(LP), 25.3% of macrophages (MC) and 1.3% of eosinophils (EO). Animal 2 presented slides with phagocytized yeast,mucus and counting of 27% of NE, 38.5% of LP, 33% of MC and 1.5% of EO...