AbstractReasons for performing study:
Rhodococcoccus equiis a significant cause of bronchopneumonia in foals worldwide. Infection of the lungs is believed to result from inhalation of virulentR. equiin dust from contaminated environments. A measure of infectious risk in an environment is the level of airborne contamination.Objectives:
To assess and compare the level of airborne virulentR. equiin paddocks and stables.Methods:
Air samples were collected sequentially over the 2003 foaling season from the paddocks and stables on 3 Irish horse breeding farms affected byR. equipneumonia. Colony blotting and DNA hybridisation techniques allowed quantitation of virulentR. equi.Results:
The odds of detecting airborne virulentR. equiin stables were 17.3 times greater than in paddocks. The median airborne concentration of virulentR. equiwas significantly higher (P<0.001) in stables than in paddocks on all farms. These observations suggested that stables were high-risk areas for infection.Conclusions and potential relevance:
Our results indicate that contaminated stables are a significant risk factor in the epidemiology ofR. equipneumonia on horse-breeding farms in a temperate climate, such as in Ireland. Management strategies that improve the air hygiene of stables, through better ventilation, use of less fragile bedding material and the use of fogging agents to reduce the airborne concentration of virulentR. equi, may reduce the incidence and severity ofR. equipneumonia on farms.