Transient diabetes mellitus in a neonatal Thoroughbred foal

Objective - To describe the clinical presentation, treatment, and outcome of a neonatal foal diagnosed with transient Type 1 diabetes mellitus.Case Summary - A 3-day-old Thoroughbred foal presented with a 24-hour history of diarrhea and depression. Coronavirus particles were observed in the feces via electron microscopy. During hospitalization the foal developed hyperglycemia concomitantly with low insulin concentration and an adequate response to exogenous insulin therapy supported a diagnosis of Type 1 diabetes mellitus. The foal required SC insulin for 26 days, but developed complications associated with insulin therapy that resolved with appropriate care. On follow up assessment the foal was found to be a healthy euglycemic animal with normal insulin concentration at 11 months of age.New or Unique Information Provided - To our knowledge this is the first report of Type 1 diabetes in this age group and the first report of transient neonatal diabetes mellitus in horses. Type 1 diabetes mellitus should be considered a differential diagnosis for hyperglycemia in equine neonates and that it can be transient and managed successfully.