Ebola: profile of a prolific killer
– Toll –
The worst outbreak of Ebola started in December 2013 in southern Guinea before spreading to two neighbouring west African countries.
It has killed more than 11,300 people, out of 29,000 registered cases, according to World Health Organization (WHO) estimates. The real figure may be higher.
More than 99 percent of the victims were based in three neighbouring West African countries — Guinea (more than 2,500 dead), Sierra Leone (more than 3,900) and Liberia (more than 4,800).
– Where does it come from ? –
Ebola was first identified in central Africa.
The tropical virus was named after a river in the Democratic Republic of Congo — then known as Zaire — where it came to light in 1976.
Five species have been identified to date (Zaire, Sudan, Bundibugyo, Reston and Tai Forest), the first being the most virulent with death rates that have reached 90 percent among humans.
– How is it transmitted ? –
The virus’ natural reservoir animal is probably the bat, which does not contract the disease itself. Chimpanzees, gorillas, monkeys, forest antelope and porcupines are also suspected of having transmitted Ebola to humans.
Only one certified contact with an animal has been recorded in the current outbreak. It has since been passed among humans.
Ebola is transmitted by contact with the blood, body fluids, secretions or organs of an infected or recently deceased person, but not by air.
Those infected do not become contagious until the symptoms appear. They then become more and more contagious until just after their death, which poses great risks during funerals.
– What are the symptoms? –
Following an incubation period of between two and 21 days, Ebola develops into a high fever, weakness, intense muscle and joint pain, headaches and sore throats. That is often followed by vomiting and diarrhoea, skin eruptions, kidney and liver failure, and internal and external bleeding.
– How to avoid infection –
In the absence of a confirmed vaccine or cure, it is recommended that preventive measures be taken to stop the spread of Ebola — notably through hand-washing and using gel or alcohol-based disinfectants.
A distance of several metres (yards) should also be kept from infected people or bodies, and healthcare providers must wear disposable protective clothing that includes masks and gloves.
– Possible treatments –
Several tests have been carried out with experimental drugs and vaccines during the epidemic in west Africa.
Among these are Avigan (favipiravir) an antiviral treatment being developed by the Japanese company Toyama Chemical.
The best known is ZMapp, a cocktail of three monoclonal (single cell) antibiotics developed through a Canadian/US partnership.
The WHO said in July that the world “is on the verge of an effective Ebola vaccine” after Canadian drug VSV-EZEBOV was found in clinical trials in Guinea to provide 100-percent protection from the disease.
The drug may therefore become the first licensed vaccine against the disease.