The team concluded that foals are susceptible to developing infection for at least the first two weeks of life before that susceptibility starts waning. Their susceptibility to disease decreases by the time they reach a month old. | Photo: The Horse Staff

At the 2014 University of Kentucky (UK) Equine Showcase, Macarena Sanz, DVM, MS, Dipl. ACVIM, a PhD candidate at UK’s Maxwell H. Gluck Equine Research Center, presented results from a two-part study evaluating foals susceptibility to R. equi.

R. equi is found worldwide and is spread through soil. R. equi infection is rare in adult horses, typically only being seen in those with underlying immune system issues.

Foals, on the other hand, are very susceptible to R. equi infections and mainly develop disease between two and five months of age, Sanz said. Clinical signs of disease are similar to those of pneumonia, including fever, lethargy, increased respiratory effort and rate, and foals usually appear distressed. The bacteria cause characteristic abscesses (or lesions) in the lungs that can become severe enough to cause death