Neonatal Septicemia - Pathology and Clinical Signs

Septicemia can be a tragic illness in neonatal and young foals. Sick foals may manifest a variety of clinical symptoms all related to a common infection and its systemic effects. While the pathogenesis of this disease is the same as for adult equids, the clinical signs seen can be very different. The rapid changes seen in foal are reflective of their low endogenous reserves of glucose and innate immune mediators as well as the poor ability to self-regulate their metabolism. The neonatal immune system is reliant on maternal antibodies at birth and development of the foal's own system takes a significant amount of time. This non-competent immune system changes how the foal responds to infection when compared to the adult. Clinical signs in septic foals include tachycardia, tachypnea, depression, anorexia, colitis, and fever. Less commonly, foals may show petechiation, swollen joints, anterior uveitis, and coma. This article is the first of a two part series on neonatal sepsis and will present a review on the neonatal immune system, the pathophysiology of sepsis, and the range of clinical signs seen in foals.