Ebola virus disease - Frequently asked questions

What is Ebola virus disease?

Ebola virus disease (EVD) (formerly known as Ebola haemorrhagic fever), is a severe, often fatal human illness caused by infection with viruses of the genus Orthoebolavirus (formerly Ebolavirus) within the Filoviridae family. To date, there are six known species of orthoebolaviruses including Ebola (formerly Zaire), Sudan, Reston, Taï Forest, Bundibugyo, and Bombali viruses, with the latter first identified in 2018. Among them, Reston and Bombali orthoebolaviruses have not yet been associated with human disease.

Ebola virus was the first orthoebolavirus ever isolated when it caused outbreaks in 1976 in the Democratic Republic of the Congo. The name of the disease comes from the first recorded outbreak in 1976 in an area that lies on the Ebola River. That same year, Sudan virus was also identified after EVD outbreaks were reported in Sudan.

Are there animal hosts?

Although the natural reservoirs for orthoebolaviruses have not been definitively confirmed, cumulative evidence particularly points towards fruit bats of the Pteropodidae family as the main natural reservoirs. Fruit bats can harbour the virus without developing clinical signs and serve as the primary source of spillover to humans and other animals. To date, virus isolation from wild bats in natural settings has not been documented, and most evidence comes from the detection of antibodies or ribonucleic acid (RNA) fragments.

Non-human primates (such as gorillas, chimpanzees and monkeys) and duikers (forest antelopes) can also be infected with orthoebolaviruses. Unlike bats, these animals usually develop severe, fatal disease and are therefore considered accidental hosts rather than long-term reservoirs.

In 2008, Reston ebolavirus was found circulating for the first time among swine in the Philippines, where intensive pig farming operations were open-air and often in close proximity to fruit trees known to be seasonally frequented by bats.

Where does Ebola occur?

Ebola virus disease occurrences are primarily constrained to tropical regions of sub-Saharan Africa. While past outbreaks mostly occurred in remote villages, recent major events have demonstrated the virus’s ability to spread to densely populated urban centres and across international borders.

Reston ebolavirus is the only orthoebolavirus species native to Asia, with the Philippines serving as its primary known geographic source. Unlike its deadly African counterparts, it is considered non-pathogenic to humans but has caused severe illness and death in non-human primates and pigs.

How does Ebola spread?

At the human-animal interface, transmission to humans occurs through handling of infected carcasses (“bushmeat”), contact with blood, tissues, other bodily fluids or excretions of infected animals (for example, fruit bats, chimpanzees, gorillas, monkeys, forest antelope or porcupines), contaminated materials, and exposure in caves or mines inhabited by bats.

Ebola viruses are spread among humans through direct contact (through broken skin or mucous membranes) with blood or body fluids from infected people who are sick with or have died from the disease, or contact with surfaces and materials that are contaminated with bodily fluids (like blood, faeces, vomit) from an infected person.

Individuals infected with Ebola cannot transmit the virus before symptoms appear. Once symptoms develop, they remain infectious as long as the virus is present in their blood and other body fluids. Health and care workers are at particularly high risk of infection when caring for Ebola patients, especially if appropriate infection prevention and control measures are not consistently followed. Traditional burial practices that involve direct contact with the body of a person who has died from Ebola can also facilitate transmission of the virus.

What should be done to protect humans from Ebola viruses?

FAO recommends following WHO guidelines about human health concerns.

Ebola virus is a lipid-enveloped virus that is highly susceptible to common hospital and chemical disinfectants, such as 0.5 percent of chlorine bleach solution, 70 percent medical ethanol and 0.2 percent peracetic acid. Practicing proper personal hygiene and avoiding contact with infected person/animals and contaminated objectives without proper PPE is essential to prevent infection.

How is EVD associated with animals?

EVD is maintained in nature through its sylvatic cycle among wildlife in rainforest areas. It is believed that the first human becomes infected through contact with an infected animal, such as a fruit bat or a non-human primate in what is called a spillover event. Spillover from wildlife to humans is rare and almost always occurs as an isolated incident. Although animals do not play a significant role once EVD starts to spread among humans, zoonotic transmission could continue occurring through infected wildlife that are hunted and prepared for human consumption may infect those that dress and prepare the carcass prior to cooking.

Pigs are the only domestic livestock species that are currently known to be susceptible to any Ebola viruses. In the Philippines, pigs have been found to be naturally infected with Ebola-Reston virus, a species of Ebola that is not known to cause human illness. Pigs are not known to be naturally infected with or transmit the more dangerous human pathogenic Ebola virus species. Nonetheless, under laboratory conditions, pigs have been infected with extremely high doses of Zaire Ebola virus and were able to transmit the disease to other pigs. 

There are no reports of other livestock species, dogs, or cats becoming sick with Ebola or spreading Ebola to people or other animals. Antibodies against Ebola viruses have been found in dogs and small ruminants in Ebola-affected areas which may point to exposure (not necessarily infection) when they have fed on infected carcasses or contaminated fruits.

For further information on susceptibility of domestic or wild animal species see FAO’s risk assessment.

Is wild meat safe to eat?

Wild meat, also called “bush meat”, refers to meat of wild animals harvested in tropical and subtropical countries, for food and non-food purposes, including medicinal use. Any that have died from unknown causes should not be handled or eaten. These animals should not be given or sold, or used to feed other animals. 

Except for bats, healthy, wild animals hunted, slaughtered, handled and consumed as wild meat present little to no risk to humans if good hygiene, proper protection and appropriate cooking practices are followed. People should not handle, slaughter, dress, sell, prepare or consume meat that originates from wild animals, or livestock, that are sick or that have died from unknown causes. 

Under no circumstances should raw wild meat or uncooked dishes based on the blood of wild animals be consumed, since these practices place people at high risk of contracting any number of infections different wildlife species are hunted as wild meat for consumption and sale, including bats, rodents, antelopes, gorillas and chimpanzees.
When assessing risk, it is important to distinguish between the many different animal species considered as wild meat.

Currently, fruit bats pose a risk to humans, since they are considered the likely reservoir of the Ebola virus. FAO recommends people in affected and at-risk areas not hunt, dress or eat bats. Other wild animals (for example, non-human primates and duikers) in areas where Ebola viruses have been detected can play a role in virus circulation at the animal-human interface. For this reason, wild animals that are sick or have died from unknown causes should not be handled or eaten. These animals should not be given or sold or used to feed other animals. 

Do wild animals pose a threat to humans of contracting Ebola?

Except for bats, healthy, live wild animals pose little Ebola threat to humans as they would show clinical signs if infected with Ebola virus.

What are good food preparation practices?

Ebola viruses, as well as other microorganisms, are not transmitted through consumption of well-cooked food. Ebola viruses are inactivated by normal temperatures used for cooking (so that food reaches at least 60°C in all parts for at least 30 minutes). It is safe to eat properly prepared and cooked meat.

Proper food preparation includes:

• Washing hands with soap before and after handling food
  
• Washing hands with soap between handling raw food and cooked or ready-to-eat food
  
• Keeping raw meat separated at all times from cooked or ready-to-eat foods
  
• Kkeeping utensils and surfaces used to prepare raw meats separated at all times from those used for other foods (for example, chopping boards, knives and plates)
  
• Promptly washing with soap and disinfecting all surfaces and utensils that have been in contact with raw meat.
  

What specific precautions should be taken by individuals involved in the wild meat trade?

FAO stresses the importance of proper precautions when hunting, handling, transporting and selling wild meat. Existing legal restrictions on the hunting or capture of wild species, particularly if endangered, should be strictly enforced.

• Hunting, handling of bats and non-human primates should be avoided.
  
• Wild meat hunters, transporters, sellers and all other intermediaries should wear gloves when dressing and handling carcasses or meat to minimize the risk of contact with bodily fluids or secretions from wildlife.
  
• As a rule, sick or dead wild animals should never be handled, sold or consumed. 
  
• Anyone who encounters significant numbers of dead wildlife should alert the proper authorities.
  
• Clean surfaces, knives, and other utensils should be used as good practice; refrigeration to avoid spoilage during transport would decrease the opportunities for other microbes to contaminate the meat. 
  

Are my livestock safe from EVD? How can I protect them?

Except for pigs, information is limited on the ability of the Ebola viruses to infect livestock, such as cattle, sheep and goats or chickens. Field surveillance studies undertaken to date have not found evidence of infection in these species, except for low levels of seroprevalence reported in sheep and goats in sporadic studies. However, livestock are susceptible to many other diseases of wildlife origin, such as Rift Valley fever, Cremean-Congo Haemorrhagic fever, African swine fever, avian influenza, rabies, brucellosis, tuberculosis, among many others. Consult the veterinary authorities for a comprehensive list of the zoonotic disease threats in your area. Farmers should protect their livestock from diseases and other health threats by implementing good animal health practices, including biosecurity and hygiene, vaccination regimes where available, limited exposure and mixing with other animals by keeping livestock in enclosures, and no feeding of raw meat, scraps or dead animals.

For more information:

• FAO Progressive Management Pathway for Terrestrial Animal Biosecurity
• FAO and WOAH guide to good farming practices for animal production food safety 
  

Can scavenging or stray animals place my family or me at risk?

The main risk of Ebola spread and infection in humans is through human-to-human transmission. Information on the ability of scavenging animals to carry the virus is limited. However, scavengers, such as stray dogs, can pose a risk by physically moving the remains of infected animals or people closer to human populations.

Can a pig farmer infected with Ebola transfer the infection to pigs?

The potential for Ebola-infected humans to subsequently infect pigs is unknown. The only Ebola virus found to infect pigs in nature is the Ebola-Reston virus found in the Philippines, which has never been reported to cause human disease. Pigs are not known to be naturally infected with or transmit the human pathogenic Ebola virus species, even though laboratory infection studies with extremely high doses of Zaire Ebola virus suggest this may occur. However, an FAO analysis determined the risk of domestic pigs becoming naturally infected and acting as carriers of the disease to be very low. In areas where Ebola is confirmed, FAO strongly advises people to keep animals in enclosures.

What is the potential impact of Ebola on agriculture and food security?

EVD outbreaks can place undue strain on health and medical services, economies, livelihoods and food systems across the most affected countries. The tragic loss of life is one of many negative impacts. During the epidemic in West Africa from 2014-2016, attempts to control the epidemic, fears of infection and overall panic caused many people to abandon their activities, including farming, taking care of livestock and marketing of products, such as milk or eggs. These can translate into loss of income and a decrease in food production and sale. It was estimated that the epidemic caused over 28 600 infections and 11 300 deaths and an estimated USD 2.8 billion to USD 32.6 billion in lost gross domestic product.

Depending on the scale and duration of the outbreak, prolonged disruption of the current harvest and subsequent planting season can drive hundreds of thousands of vulnerable people deeper into poverty and hunger as food sources dwindle.

What can be done to reduce the impact of Ebola outbreak-related crises on food security and livelihoods?
As soon as any outbreak is fully controlled, interrupted agriculture practices must be revived where possible and alternative sources of food and income identified to safeguard the livelihoods and food security of those most affected.

FAO continues to assist countries cope with food security crises related to disease outbreaks and revive disrupted livelihoods. FAO works with governments to provide training, inputs, tools and expertise to promote food security via support to the agriculture sector.

What are the negative repercussions of stigma/fear of EVD survivors on agriculture?

Survivors of EVD do not pose a threat to their community, and all survivors, their partners and families should be shown respect, dignity and compassion. The stigma faced by Ebola survivors represents a serious threat to food security. Scientifically unwarranted fear of infection via an Ebola survivor can cause customers to stop frequenting a survivor’s shop, to cease to purchase produce or animal products from agrarian survivors and to exclude survivors from agriculture and income generating activities.

What is FAO doing to reduce the likelihood of epidemics of EVD and other zoonotic diseases in the future?

FAO collaborates with national governments, international organizations, and local partners to enhance understanding of the drivers of zoonotic disease emergence and transmission. Through a One Health approach, FAO supports the strengthening of surveillance, disease detection, and intelligence systems in collaboration with partners, including through the Global Early Warning System (GLEWS+) for health threats and emerging risks at the human–animal–ecosystem interface. These efforts contribute to the prevention, detection, and response to zoonotic diseases such as Ebola virus disease (EVD), Marburg virus disease, and mpox.

FAO is working with the Africa Centres for Disease Control and Prevention (Africa CDC), InterAfrican Bureau for Animal Resources (AU-IBAR), WHO and other partners on zoonotic disease risk management through a One Health approach. This includes active participation in the African continental Incident Management Support Team (IMST) and other regional/national coordination mechanisms. 

FAO also supports risk communication and community engagement initiatives to raise awareness of zoonotic disease risks and promote culturally appropriate risk mitigation practices. Attention is given to communities that rely on wildlife for food and livelihoods, helping to reduce the risk of spillover of Ebola viruses and other zoonotic pathogens from wildlife to human populations.

To support preparedness and response efforts, FAO assists countries in strengthening early warning systems, laboratory diagnostic capacity, field investigations, workforce training, and the development or revision of national preparedness and response plans. In addition, FAO can provide personal protective equipment (PPE), laboratory reagents, field investigation equipment and other essential operational materials to support outbreak response activities.

FAO further supports resource mobilization efforts through engagement with the Pandemic Fund, governments and other implementing entities. This includes exploring the reprogramming of ongoing Pandemic Fund projects and fast-tracking approval of new proposals for affected and at-risk countries, as well as mobilizing supplementary resources through emergency Technical Cooperation Programme (eTCP) projects, the Special Fund for Emergency and Resilience Activities, and other emergency financing mechanisms to strengthen preparedness and response capacities.

Where can I get more information about Ebola?

World Health Organization 
World Organisation for Animal Health (WOAH) 
Africa Centre for Disease Control 
European Centre for Disease Prevention and Control (ECDC)  
U.S. Centers for Disease Control and Prevention