Rhodococcus Equi

Rhodococcus equi is a Gram-positive facultative intracellular pathogen that is a common cause of bronchopneumonia in foals between 3 weeks and 5 months of age. R. equi can also cause various extrapulmonary infections. Although R. equi can be cultured from the environment of virtually all horse farms, the clinical disease in foals is endemic at some farms and only sporadic at others. Infections are extremely rare in adult horses.

The most common clinical manifestation of R. equi infections in foals is bronchopneumonia. Early clinical signs may only include a slight increase in respiratory rate and a mild fever. These subtle clinical signs are often either missed or ignored, allowing the condition to progress. As the disease progresses, clinical signs might include decreased appetite, lethargy, fever, tachypnea, increased effort of breathing characterized by nostril flaring, and increased abdominal effort.