Introduction

Ebola is the name of a river situated near the village Yambuku in Congo. Two simultaneous outbreaks of this disease were reported in this region in 1976; hence the name Ebola. Ebola virus belongs to theFiloviridaefamily, and the disease resulting from Ebola virus is considered aViral Hemorrhagic Fever(VHF) a label used to refer to a multisystem syndrome in which damage to vascular system occurs which causes hemorrhage that may be life-threatening. The main natural reservoirs of viruses that cause VHF are arthropods and rodents. As far as Ebola virus is concerned, bats have been considered to be a major natural reservoir of this virus; the evidence to support this notion is however contradictory.

Transmission and course of disease

During an outbreak, the first individual to be infected with Ebola virus is thought to acquire the infection through direct contact with an animal that harbors the virus. Transmission between humans takes place through direct contact with patients body secretions including saliva, blood and semen. A person infected with Ebola virus does not spread the disease until s/he begins to manifest it's symptoms; moreover, spread through the air does not take place.The typical course of Ebola virus infection spans over two to three weeks. The initial symptoms of the disease include myalgia, fever and malaise which are interpreted by the patient as a flu-like illness. As the disease progresses, patients manifest severe bleeding along with coagulation abnormalities. Neutrophilia (elevated neutrophil count), lymphopenia (low lymphocyte count) along with a skin rash and gastrointestinal bleeding are commonly observed in such patients. The inflammatory response that develops is not protective and in most cases it is exaggerated. Worsening viremia (viral presence in blood) and the resulting liver damage may result in disseminated intravascular coagulopathy (DIC) a disorder which results from over activity of proteins that control blood clotting. The integrity of blood vessels is further compromised since the virus directly infects the endothelial cells of blood vessels at this stage. The ultimate outcome of this process is a hypotensive shock that results due to excessive bleeding.

Diagnosis, Treatment and Prognosis

Confirmation of diagnosis based on signs and symptoms is not a possibility. Therefore, tests like ELISA, Polymerase Chain Reaction (PCR), detection of IgM and IgG antibodies and Immunohistochemistry testing are used at various stages of the disease to confirm the diagnosis. No vaccine for protection against the disease is as yet available. Treatment is mainly supportive, which includes administration of intravenous fluids, maintaining balance of electrolytes, oxygen support, maintenance of blood pressure and the treatment of secondary infections. Ebola infection is associated with an unfavorable prognosis and the mortality rate may be as high as 90%; however, early detection and diagnosis of the disease may bring forth comparatively better outcomes.