OIE experts review current knowledge on Ebola virus disease
The World Organisation for Animal Health (OIE) has issued a technical information sheet on Ebola virus disease outlining epidemiological observations and scientific knowledge of the disease including the animal reservoir.
Paris, 6 October 2014 – The OIE technical information sheet on Ebola virus disease has been prepared and reviewed by internationally regarded scientific experts, including experts from OIE global Reference Centres and Working Group on wildlife, and was subsequently endorsed by the OIE Scientific Commission on Animal Diseases.
Ebola virus disease (EVD), also known as Ebola haemorrhagic fever is a severe contagious disease affecting humans and non-human primates, such as gorillas, chimpanzees and some other monkeys. It mainly occurs in the Central and West African regions and can be transmitted to humans from an infected animal or human. Hence, Ebola virus disease is a zoonosis and poses significant threats to public health by causing hemorrhagic fever outbreaks in humans with a high case fatality rate. At present, there is no licensed therapeutic or vaccine for humans. Experimental drugs and vaccines are being developed.
The virus was reported again in humans at the beginning of 2014 in Guinea and then Liberia. It has since then spread to Sierra Leone and most recently to Nigeria to become the largest Ebola outbreak in history and the first in West Africa. In August 2014, the WHO declared the outbreak as an international health emergency. An unrelated outbreak was also reported in Democratic Republic of Congo (DRC).
Although the strain causing the current outbreak has resulted in an unprecedented number of fatalities, the initial source of the virus remains unclear. However it is likely that the initial introduction to the human population was from a wild animal source to a single person. The disease is now being transmitted between humans and there is no evidence that animals continue to play a role in spreading the virus.
Field studies and epidemiological surveys demonstrate that the natural reservoir hosts for this virus may be fruit bats, without showing clinical signs. These results still need to be further investigated.
Ebola is most likely initially transmitted from animals such as bats and non-human primates to humans through hunting and collection of sick or dead wild animals and handling or consumption of uncooked bush meat. In rural areas fruit bats are a popular source of forest meat for humans and are prepared by hand to be dried, smoked and/or cooked. Infection could also be transmitted to humans by handling or consumption of forest fruits contaminated with bat saliva or faeces in affected areas.
Therefore the OIE is in full accordance with World Health Organization (WHO) recommendations to avoid contact with wild animals, including bats, monkeys and rodents, in affected areas.
The OIE encourages the national Veterinary Services of the countries affected to remain vigilant and strengthen the monitoring of wildlife. In collaboration with OIE experts, it will continue to work and regularly update guidance to its Members and the public on this disease.