The Ebola virus, or ‘Death Virus’ is a major concern due to the recent outbreak across West Africa, in countries such as Sierra Leone, Guinea and Liberia. The disease is now at an international scale, with precautions even being taken to prepare in the UK. So, what is Ebola and how is it so deadly?
The Ebola virus has been found in five different strains, four of which have been known to affect humans. If you were to look at an electron micrograph of members of the ‘Ebolavirus’ genus, you would see their characteristic thread-like structure. The virus can be transmitted to humans from the carcasses of primates such as gorillas and chimpanzees, usually to one individual. The virus is then spread to other persons through contact of bodily fluids.
The spread of Ebola that has led to an epidemic has occurred in poor hospital conditions, where safety precautions have not been properly carried out, or are simply unknown. A person is said to be infected with the virus for as long as it remains in their blood. The incubation period ranges from 2-21 days over which symptoms appear suddenly and can vary between cases. Many symptoms are mistaken for malaria and can include high fever, headache, joint pain, and both internal and external bleeding. In the later stages the symptoms worsen and can include haemorrhaging, purpura and petechia. Interior bleeding is said to be caused by the reaction between the virus and platelets. These platelets then cut cell-sized holes into the capillary walls. By the second week of infection, the fever will either lessen, or the patient will experience multi-organ failure. The cause of death is usually hypovolemic shock or multi-organ failure.
As Ebola is a virus, it does not replicate through cell division, rather it uses a host cell to multiply and assemble itself in the cell. For a virus to invade a host cell, there must be some sort of molecule on the surface of the host cell to be used as recognition for the virus. Such a molecule is called a receptor. The cell must possess that particular receptor for the virus to enter, otherwise the virus cannot invade. This comes to show that it is important for scientists to find out which receptor it is that the virus uses, as it can be used to help to develop a vaccine or other cure to prevent the virus from invading.
The development of a cure is desperately needed as mortality rates for the disease are very high. There is no specific licensed vaccine or other standard treatment. Since patients are usually dehydrated, doctors mainly work to replace electrolyte imbalance and maintain blood levels. At present, the development of effective and rapid-working vaccines is ongoing.
Carcass- The dead body of an animal
Electrolyte- The ionised parts of a living cell, blood, or other organic matter
Haemorrhage- An escape of blood from a ruptured blood vessel
Hypovolemic shock- An emergency condition in which severe blood and fluid loss make the heart unable to pump enough blood to the body
Incubation period- The period between exposure to an infection and the appearance of the first symptoms
Mortality rates- The number of deaths in a given area or period, or from a particular cause
Petechia- A small red or purple spot caused by bleeding to the skin
Platelets- A cell fragment found in large numbers in the blood which is involved in blood clotting
Purpura- A rash of purple sports on the skin caused by internal bleeding from small blood vessels