Ebola virus, clinical symptoms

People infected with Ebola virus suddenly experience fever, severe headache and muscle pain, malaise, extreme asthenia, conjunctivitis, occasionally a papular rash, dysphagia, nausea and vomiting, bloody diarrhoea followed by diffuse haemorrhages (particularly from the mucosa), delirium, shock and ARDS. Only 5% of the patients have jaundice. In addition to functional blood platelet disturbances there is always also thrombocytopenia. Initially there is lymphocytopenia and later neutrophilia. Histologically there is focal necrosis in various organs (testes, kidneys, liver, etc.). The haemorrhages, which may occur in such infections are partly caused by invasion of and damage to vascular endothelial cells. A component of the glycoprotein coat of the virus is toxic to vascular endothelial cells. The immunological course early in the infection determines how quickly the Ebola virus replicates and whether the host will die or recover. Surviving an infection is linked to an early appearance of IgM and IgG, followed by the activation of cytotoxic cells. People die if their humoral defence system is disturbed and T cell activation is too late to prevent virus replication. The role of several cytokines (IL-1β, IL-6 and TNF) is being investigated. The production of these cytokines is stimulated among other things by activated endothelial cells. Asymptomatic infection with Ebola can occur. The virus isolated from these individuals is wild type rather than a less virulent variant.

Category: Medical Subject Notes , Medicine Notes