Caterpillars emerge as possible cause for syndrome killing foals .
Menu Help Tips . Caterpillars emerge as possible cause for syndrome killing foals Scientists trying to identify the mysterious illness that is killing newborn horses and threatening Kentucky's thoroughbred industry are looking at caterpillars as a possible culprit. Intensive Care Unit Technician, Kevin Simone, treats a recovering foal with antibiotics at Rood and Riddle Eqine Hospital in Lexington. Scientists trying to identify the mysterious illness that is killing newborn horses and threatening Kentucky's thoroughbred industry are looking at caterpillars as a possible culprit. Experts have been working around the clock for the past three weeks to figure out why a startling number of foals are dying and mares are suffering spontaneous abortions.