Rhodococcus equi, a Gram-positive facultative intracellular pathogen, is one of the most common causes of pneumonia in foals 1-6 month of age. While it can cause significant economic losses, researchers are still working to understand how and why it develops and how to prevent it.
The pathogen is ubiquitous—it can be cultured from the environment of basically all horse farms. Despite that fact, not all farms see clinical cases; disease occurrence ranges from endemic, sporadic, or nonexistent. Read more here.