Is it possible for Ebola to spread out of Africa?

Is it possible for Ebola to escape Africa and spread to other countries? If so, how?

Is it possible for Ebola to spread out of Africa?
The 2022 Ebola outbreak is centered in Uganda. Can Ebola spread out of Africa?

The Ebola virus is spreading rapidly in Uganda, and many are wondering if it's possible for the disease to spread out of the continent. In this blog post, we'll take a look at some of the factors that would need to be in place for Ebola to spread beyond Africa. We’ll examine Ebola as a disease, learn about virology, study how Ebola is transmitted, and use what we learned to answer our main question: is it possible for Ebola to escape Africa and spread to other countries?

What is Ebola?

Ebola virus disease (EVD), also known as Ebola, is a serious and deadly virus that affects humans and primates. EVD is caused by the Ebola virus. The virus is spread through contact with the blood or body fluids of an infected person and can lead to death in 25-90% of cases. Early symptoms include fever, muscle pain, and headaches, followed by vomiting, diarrhea, and internal and external bleeding. Death typically occurs 6-16 days after symptoms appear. There is no specific treatment for Ebola at this time; however early diagnosis and supportive care can improve the chances of survival.

Where did Ebola come from?

The Ebola virus is introduced to the human population through contact with the bodily fluids of an infected animal. The first documented case of EVD in the West Africa outbreak (2014 to 2016) suggests that infection is possible through exposure to bats. In addition to bats, other animals known to be infected with Ebola include chimpanzees, gorillas, and Forest antelopes. Cases have been documented in people who handled these animals, both dead and alive, in Cote d’Ivoire, the Republic of the Congo, and Gabon.

The Ebola virus is believed to have originated in fruit bats from the Pteropodidae family. These bats are called the “natural reservoir” of the disease. Non-human primates are known to be susceptible to the virus and have been a source of human infection in previous EVD outbreaks. However, they are considered incidental hosts as they typically develop severe, fatal illnesses when infected and viral circulation is not believed to persist within their populations.

How do people catch Ebola?

In order to see how Ebola can spread beyond Africa, we need to first understand how someone can catch the disease and pass it on to others. Ebola has been seen to spread in a number of ways, including via infected body fluids, handling of dead bodies, sexual intercourse, and in laboratories.

Infected body fluids

The Ebola virus is a deadly disease that can be transmitted from person to person through direct contact with the blood, organs or other bodily fluids of an infected person. People can also become infected with the Ebola virus through contact with objects, such as needles or soiled clothing, that have been contaminated with infectious liquids and fluids.

Handling bodies for burial

Burial practices that involve direct contact with the body of an infected person may also contribute to transmission. This is because when the body is being prepared for burial, fluids can be released from the mouth, nose, or eyes which contain high concentrations of the Ebola virus. Furthermore, the body is often handled without protective clothing, increasing the risk of transmission.

Sexual transmission

The Ebola virus is a serious threat to anyone it comes in contact with. Even after acute illness, the virus can persist in some areas of the body, including the testes, interior of the eyes, placenta, and central nervous system. Sexual contact with a convalescent case or survivor has been documented as a method of transmission. The virus can be present in semen for many months after recovery.

Healthcare settings and lab accidents

When infection control measures are insufficient or barrier nursing precautions aren't implemented, healthcare workers are at risk of catching EVD from patients. There have been reports of laboratory-acquired EVD infections in England (in 1976) and Russia (in 1996 and 2004).

Transmissibility of Ebola

A person's infectiousness changes over time following infection with the Ebola virus. When a person is displaying no symptoms, or early symptoms such as fever, the level of the virus in the body is very low and poses little risk to others. However, once an individual becomes unwell with more severe symptoms like diarrhea and vomiting, all their body fluids become highly infectious. At this stage, blood, feces and vomit are particularly dangerous to other people. Once someone reaches the point where they are most infectious, they usually aren't well enough to move around or interact socially much anyway. So at this stage of disease, the greatest risk is to those who come into close contact with them for caretaking purposes. Skin can also become contaminated in late-stage disease due to poor hygiene conditions.

Ebola transmission diagram.
A diagram showing how a person can transmit Ebola with differing levels of risk as the illness develops. Source:

Is it possible for Ebola to escape Africa and spread to other countries?

In short, it is absolutely possible for Ebola to escape Africa and spread to other countries and continents. The way Ebola is spread makes it very easy for someone to acquire to disease and pass it to others before even noticing they are sick. The disease has reached other countries, including the United States, in prior outbreaks.

The virus has caused outbreaks in several African countries, and there is a risk that it could potentially reach other continents through infected people traveling from Africa. There have been cases of Ebola being imported into Europe and North America, but so far the disease has not been able to establish itself consistently outside of Africa.

Countries that have experienced Ebola outbreaks

The table below shows a list of countries that have experienced Ebola outbreaks.

DateCountry[a]VirusHuman casesHuman deathsCase fatality rateDescription
Jun–Nov 1976 SudanSUDV28415153%Occurred in Nzara (the source town), Maridi, Tumbura, and Juba (cities in present-day South Sudan). The index cases were workers in a cotton factory. The disease was spread by close contact with an acute case, usually from patients to their nurses. Many medical care personnel were infected.[19]
Aug 1976 ZaireEBOV31828088%Occurred in Yambuku and surrounding areas in what was then Zaire (present-day Democratic Republic of the Congo DRC). It spread through personal contact and by use of contaminated needles and syringes in hospitals and clinics.[20]
Aug–Sep 1979 SudanSUDV342265%Occurred in Nzara and Maridi. This was a recurrent outbreak at the same site as the 1976 Sudan epidemic.[21]
Dec 1994–Feb 1995 GabonEBOV523160%Occurred in Makokou and gold-mining camps deep in the rainforest along the Ivindo River. Until 1995, the outbreak was incorrectly classified as yellow fever.[22]
May–Jul 1995 ZaireEBOV31525481%Occurred in Kikwit and surrounding areas. The outbreak was traced to a patient who worked in a forest adjoining the city. The epidemic spread through families and hospital admissions.[23][24]
Jan–Apr 1996 GabonEBOV312168%Occurred in the village of Mayibout 2 and neighboring areas. A chimpanzee found dead in the forest was eaten by villagers hunting for food. Nineteen people involved in the butchery of the animal became ill, and other cases occurred in their family members.[22]
Jul 1996–Mar 1997 GabonEBOV604575%Occurred in the Booué area with transport of patients to Libreville. The index case-patient was a hunter who lived in a forest timber camp. The disease was spread by close contact with infected persons. A dead chimpanzee found in the forest at the time was determined to be infected.[22]
Oct 2000–Jan 2001 UgandaSUDV42522453%Occurred in the Gulu, Masindi, and Mbarara districts of Uganda. The three greatest risks associated with Sudan virus infection were attending funerals of case-patients, having contact with case-patients in one's family, and providing medical care to case-patients without using adequate personal protective measures.[25] Victims included Matthew Lukwiya.
Oct 2001–Jul 2002 GabonEBOV655382%Occurred on both sides of the border between Gabon and the Republic of the Congo.
Oct 2001–Jul 2002Flag of the Republic of the Congo.svg ROCEBOV594475%Occurred on both sides of the border between Gabon and the Republic of the Congo (RC). This outbreak included the first reported occurrence of Ebola virus disease in the RC.[26]
Dec 2002–Apr 2003Flag of the Republic of the Congo.svg ROCEBOV14312890%Occurred in the districts of Mbomo and Kelle in the Cuvette-Ouest Department.[27]
Nov–Dec 2003Flag of the Republic of the Congo.svg ROCEBOV352983%Occurred in Mbomo and Mbandza villages, located in Mbomo District in the Cuvette-Ouest Department.[28]
Apr–Jun 2004 SudanSUDV17741%Occurred in Yambio county in Western Equatoria of southern Sudan (present-day South Sudan). This outbreak was concurrent with an outbreak of measles in the same area, and several suspected EVD cases were reclassified later as measles cases.[29]
Apr-May 2005Flag of the Republic of the Congo.svg ROCEBOV121083%Occurred in the Etoumbi district of Cuvette Ouest Department of the Republic of the Congo [30]
Aug–Nov 2007Flag of the Democratic Republic of the Congo.svg DRCEBOV26418771%
Dec 2007–Jan 2008 UgandaBDBV1493725%Occurred in the Bundibugyo District in western Uganda. This was the first identification of the Bundibugyo virus (BDBV).[3][4]
Dec 2008–Feb 2009Flag of the Democratic Republic of the Congo.svg DRCEBOV321445%Occurred in the Mweka and Luebo health zones of the Kasaï-Occidental province.[31]
Jun–Aug 2012 UgandaSUDV241771%Occurred in the Kibaale District.[32]
Jun–Nov 2012Flag of the Democratic Republic of the Congo.svg DRCBDBV572951%Occurred in the Orientale Province.[1][33]
Dec 2013–Jun 2016Widespread:
 Sierra Leone
Limited and local:
 United States
 United Kingdom
EBOV28,61611,31070–71% (general)[34][35][36][note 1]
57–59% (among hospitalized patients)[37]
This was the most severe Ebola outbreak in recorded history in regards to both the number of human cases and fatalities. It began in Guéckédou, Guinea, in December 2013 and spread abroad.[38][39][34] Flare-ups of the disease continued into 2016,[40] and the outbreak was declared over on 9 June 2016.
Aug–Nov 2014Flag of the Democratic Republic of the Congo.svg DRCEBOV66[41]49[41]74%Occurred in Équateur province. Outbreak detected 24 August and, as of 28 October 2014, the WHO said that twenty days had passed since the last reported case was discharged and no new contacts were being followed.[41][42] Declared over on 15 November 2014.[43]
May–Jul 2018Flag of the Democratic Republic of the Congo.svg DRCEBOV543361%

On 8 May 2018, the government of the Democratic Republic of the Congo reported two confirmed cases of Ebola infection in the northwestern town of Bikoro.[44] On 17 May, a case was confirmed in the city of Mbandaka.[45] Health authorities were planning to ring vaccinate with rVSV-ZEBOV, a recently developed experimental Ebola vaccine, to contain the outbreak.[45][46] The outbreak was ongoing as of 24 June 2018, in 2014 a different area of Equateur province was affected[47][48] On 24 July 2018 the outbreak was declared over.[49][50][51][52]

Aug 2018–Jun 2020Widespread:
Flag of the Democratic Republic of the Congo.svg DRC
Limited and local:

On 1 August 2018, the Democratic Republic of the Congo Ministry of Health declared an outbreak when 4 individuals tested positive for the Ebola virus.[55][56][57][58] On 11 June 2019, the WHO confirmed that a five-year-old boy in Uganda died after being diagnosed with Ebola.[59][60] On 25 June 2020, the second biggest EVD outbreak ever was declared over.[61]

May 2020–Nov 2020Flag of the Democratic Republic of the Congo.svg DRCEBOV1305542%On 31 May 2020, the DRC Health Minister Eteni Longondo announced an additional Ebola outbreak, separate to the ongoing Kivu Ebola epidemic. The outbreak originated in Équateur province (which was also the location of the 2018 Équateur province Ebola outbreak).[62][63][64] By 17 October 2020, the case count was 128 with 53 fatalities.[65]

By 18 November 2020, the World Health Organization and the Congolese government had not received reports of any cases of Ebola in Équateur province or all of the DRC for 42 days.[66] When the outbreak was declared over, there were 130 reported cases and 55 reported fatalities due to the virus.[67]

Feb–May 2021Flag of the Democratic Republic of the Congo.svg DRCEBOV12650%On 6 February 2021, an outbreak was declared in Butembo in the North Kivu province by the Ministry of Public Health of the Democratic Republic of the Congo.[68] By 3 May 2021, the outbreak was declared over.[69]
Feb–Jun 2021 GuineaEBOV231252%First Ebola cases and deaths in the country since 2016.[68][70] The first cases were confirmed on 14 February 2021, and by 9 April 2021, there were 23 reported cases of the virus, with 12 fatalities and 9 recoveries.[71] Scientists concluded that the likely source of the outbreak was a man who had survived the 2013-2016 West African epidemic but had unknowingly harbored the Ebola virus in his body, eventually transmitting it to somebody in his community, although the first known case of this current outbreak was a female nurse who had died on 28 January 2021.[72] The outbreak was declared over on 19 June 2021.[73]
Oct–Dec 2021Flag of the Democratic Republic of the Congo.svg DRCEBOV11982%On 8 October 2021, the Ministry of Public Health for the Democratic Republic of the Congo reported a new laboratory confirmed case of Ebola virus disease, ten more related cases were later confirmed.[74] On 16 December the outbreak was declared over.[75]
Sept 2022–Flag of Uganda.svg UGASUDV12632On 20 September 2022 an outbreak was declared in Mubende District, Uganda. Twenty-three people died, with a total of 36 cases detected. The situation is currently ongoing.[76]

Minor or single-case outbreaks have also taken place. A list of countries that have experienced this level of Ebola spread are shown below.

DateCountry[a]VirusHuman casesHuman deathsDescription
1976 United KingdomSUDV or EBOV[note 2]10Laboratory infection by accidental stick of contaminated needle.[77][78]
1977 ZaireEBOV11Noted retroactively in the village of Tandala.[78][79][80]
1989–1990 PhilippinesRESTV3[b]0The Reston virus (RESTV) was first identified when it caused high mortality in crab-eating macaques in a primate research facility responsible for exporting animals to the United States.[81] Three workers in the facility developed antibodies to the virus but did not get sick.[82]
1989 United StatesRESTV00RESTV was introduced into quarantine facilities in Virginia and Pennsylvania by monkeys imported from the Philippines. No human cases were reported.[83]
1990 United StatesRESTV4[b]0Monkeys imported from the Philippines introduced RESTV into quarantine facilities in Virginia and Texas. Four humans developed antibodies but did not get sick.[84]
1992 ItalyRESTV00RESTV was introduced into quarantine facilities in Siena by monkeys imported from the same facility in the Philippines that was the source of the 1989 and 1990 U.S. outbreaks. No human cases resulted.[85]
1994 Côte d'Ivoire[c]TAFV10This case was the first and thus far only recognition of Taï Forest virus (TAFV). Approximately one week after conducting necropsies on infected western chimpanzees in Taï National Park, a scientist contracted the virus and developed symptoms similar to those of dengue fever. She was discharged from a Swiss hospital two weeks later and fully recovered after six weeks.[86]
1995 Côte d'IvoireUnknown10One person, fleeing the civil war in neighboring Liberia, was identified as an Ebola case in Gozon. This is considered as a suspected case, excluding from the WHO outbreak counts.[87][88]
1996 South AfricaEBOV11n/a
1996 United StatesRESTV00RESTV was again introduced into a quarantine facility in Texas by monkeys imported from the same facility in the Philippines that was the source of the 1989 and 1990 U.S. outbreaks. No human cases resulted.[89]
1996 PhilippinesRESTV00RESTV was identified at a monkey export facility in the Philippines. No human cases resulted.[90]
1996 RussiaEBOV11Laboratory contamination.[91]
2004 RussiaEBOV11Laboratory contamination.[92]
2008 PhilippinesRESTV6[b]0First recognition of RESTV in pigs. Strain very similar to earlier strains. Occurred in November. Six workers from the pig farm and slaughterhouse developed antibodies but did not become sick.[93][94]
2011 UgandaSUDV11n/a[citation needed]
2012 UgandaSUDV74n/a[citation needed]
2015 PhilippinesRESTV00On 6 September 2015, the Philippine health secretary reported an outbreak of RESTV in a primate research and breeding facility. Twenty-five workers subsequently tested negative for the virus.[95]
2017Flag of the Democratic Republic of the Congo.svg DRCEBOV84

On 11 May 2017, the Ministry of Public Health for the Democratic Republic of the Congo notified the WHO of an Ebola outbreak in the Likati health zone (LHZ) in Bas-Uele province, in the northern part of the country. Suspected infections were reported from Nambwa, Mouma, and Ngay. The LHZ borders the Central African Republic, which made this outbreak a moderate risk to the region.[96][97]

2018 HungaryN/A00On 20 April 2018, a laboratory accident led to a single worker being exposed to the Ebola virus, though he did not develop symptoms.[98][99]
2022Flag of the Democratic Republic of the Congo.svg DRCEBOV55An outbreak in DRC began on April 23, and has killed 100% of those infected.[100]
2022Flag of the Democratic Republic of the Congo.svg DRCEBOV11A single case was confirmed in North Kivu.[101]

Note that many of these countries are not in Africa.

Has Ebola spread to other countries outside of Africa in 2022?

So far, in 2022, no countries outside of Africa have seen Ebola cases. For now, the current outbreak seems to be confined to Uganda. However, this could possibly change. Growing interconnectivity and globalization will make it potentially easier for new diseases to spread.

Ebola Situation Report: Chicago
Chicago Ebola cases and deaths. Ebola and Chicago public health. Updated 2023. tracks global data on the 2022 Ebola virus disease outbreak. You can refer to the United States page to track the number of Ebola cases in the United States in 2022. Because the site is updated daily, this will be one of the first places you will be able to go to view information about any Ebola outbreak in the United States. We will also aggregate and share any information about the number of American Ebola cases and deaths on our Twitter account, so be sure to follow it for up-to-date information on the 2022 Ebola outbreak.