Pathology, Infectious Agents And Horse- And Management-Level Risk Factors Associated With Signs Of Respiratory Disease In Ethiopian Working Horses

Background Respiratory disease is a common cause for presentation of working horses to clinics in Ethiopia and a priority concern for owners. Objectives To identify risk factors for and association of pathogens with respiratory signs in working horses. Study design Unmatched case-control study. Methods Cases were those animals recently coughing (last 7 days) or observed with coughing, nasal discharge or altered respiration at the time of examination. A physical exam and respiratory endoscopy were performed including a tracheal wash sample to detect the presence of pathogens and serology performed on blood. An owner questionnaire was administered. Risk factors were determined using multivariable logistic regression. Results Data on 108 cases and 93 unmatched control horses were obtained. Case horses often had underlying lower airway pathology and were significantly more likely to haveStreptococcus zooepidemicusdetected (OR: 12.4, 95% CI: 3.6-42.4). There was no evidence of a major role for viral respiratory pathogens. Risk factors included completion of strenuous work (OR: 2.7, 95% CI: 1.2-6.3), drinking from stagnant water sources (OR: 2.3, 95% CI: 1.0-5.2) or being housed on a cobbled floor (OR: 2.0, 95% CI: 1.1-3.8). There were increased odds of respiratory disease in young and old horses in this population. Main limitations Samples for pathogen detection and cytology were only taken from the trachea. Conclusion S. zooepidemicus, a common commensal, may play a role in clinical respiratory disease in this population.