Neonatal sepsis - Pathology and clinical signs

Sepsis, also known as septicaemia, is defined as a dysregulated host systemic inflammatory response to infection. Neonatal sepsis is one of the main diseases that can affect young foals with a short-term survival rate of only 50%-60%. While the pathogenesis of this disease is the same as for adult equids, the clinical signs seen can be very different. Sick foals may manifest a variety of clinical signs all related to a common infection and its systemic effects including tachycardia, tachypnoea, depression, anorexia, colitis, and fever. Less commonly, foals may show petechiation, swollen joints, anterior uveitis, and coma. The rapid changes seen in foals 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. Given the significant range of clinical signs and comorbidities, the prognosis for a full athletic career can vary from grave to excellent when compared to their healthy counterparts.