The disease typically occurs in outbreaks in tropical regions of
Sub-Saharan Africa. The largest outbreak to date was the
Ebola virus epidemic in West Africa, which caused a large number of deaths in
Guinea,
Sierra Leone, and
Liberia.
1976 Sudan The first known outbreak of EVD was identified only after the fact. It occurred between June and November 1976, in
Nzara, South Sudan (then part of
Sudan), and was caused by
Sudan virus (SUDV). The Sudan outbreak infected 284 people and killed 151. The first identifiable case in Sudan occurred on 27 June in a storekeeper in a cotton factory in
Nzara, who was hospitalised on 30 June and died on 6 July. Although the WHO medical staff involved in the Sudan outbreak knew that they were dealing with a heretofore unknown disease, the actual "positive identification" process and the naming of the virus did not occur until some months later in
Zaire. This outbreak was caused by EBOV, formerly designated
Zaire ebolavirus, a different member of the
genus Ebolavirus than in the first Sudan outbreak. The
first person infected with the disease was the village school's headmaster
Mabalo Lokela, who began displaying symptoms on 26 August 1976. Lokela had returned from a trip to Northern Zaire near the border of the
Central African Republic, after visiting the
Ebola River between 12 and 22 August. He was originally believed to have
malaria and was given
quinine. However, his symptoms continued to worsen, and he was admitted to Yambuku Mission Hospital on 5 September. Lokela died on 8 September 14 days after he began displaying symptoms. Soon after Lokela's death, others who had been in contact with him also died, and people in Yambuku began to panic. The country's Minister of Health and Zaire President
Mobutu Sese Seko declared the entire region, including Yambuku and the country's capital,
Kinshasa, a quarantine zone. No-one was permitted to enter or leave the area, and roads, waterways, and airfields were placed under
martial law. Schools, businesses and social organisations were closed. The initial response was led by Congolese doctors, including
Jean-Jacques Muyembe-Tamfum, one of the discoverers of Ebola. Muyembe took a blood sample from a Belgian nun; this sample would eventually be used by
Peter Piot to identify the previously unknown Ebola virus. Muyembe was also the first scientist to come into direct contact with the disease and survive. Researchers from the
Centers for Disease Control and Prevention (CDC), including Piot, co-discoverer of Ebola, later arrived to assess the effects of the outbreak, observing that "the whole region was in panic." Piot concluded that Belgian nuns had inadvertently started the epidemic by giving unnecessary vitamin injections to pregnant women without sterilizing the syringes and needles. The outbreak lasted 26 days and the quarantine lasted two weeks. Researchers speculated that the disease disappeared due to the precautions taken by locals, the quarantine of the area, and discontinuing of the injections. The virus responsible for the initial outbreak, first thought to be the
Marburg virus, was later identified as a new type of virus related to the genus
Marburgvirus. Virus strain samples isolated from both outbreaks were named "Ebola virus" after the
Ebola River, near the first-identified viral outbreak site in Zaire. or Belgian researchers. Subsequently, a number of other cases were reported, almost all centred on the Yambuku mission hospital or close contacts of another case. Although the two outbreaks were at first believed connected, scientists later realised that they were caused by two distinct ebolaviruses, SUDV and EBOV. In 2004, a Russian scientist died from Ebola after
sticking herself with an infected needle. Between April and August 2007, a fever epidemic in a four-village region of the DRC was confirmed in September to have been cases of Ebola. Many people who attended the recent funeral of a local village chief died. The WHO reported 149 cases of this new strain and 37 of those led to deaths. in the eastern region. Other than its discovery in 2007, this was the only time that this variant has been identified as responsible for an outbreak. The WHO revealed that the virus had sickened 57 people and killed 29. The probable cause of the outbreak was tainted
bush meat hunted by local villagers around the towns of
Isiro and Viadana. In 2014, an outbreak occurred in the DRC.
Genome-sequencing showed that this outbreak was not related to the
2014–15 West Africa Ebola virus outbreak, but was the same
EBOV species, the Zaire species. It began in August 2014, and was declared over in November with 66 cases and 49 deaths. This was the 7th outbreak in the DRC, three of which occurred during the period when the country was known as
Zaire.
2013–2016 West Africa In March 2014, the
World Health Organization (WHO) reported a major Ebola outbreak in
Guinea, a West African nation. Researchers traced the outbreak to a one-year-old child who died in December 2013. The disease rapidly spread to the neighbouring countries of
Liberia and
Sierra Leone. It was the largest Ebola outbreak ever documented, and the first recorded in the region. By mid-August 2014,
Doctors Without Borders reported the situation in Liberia's capital,
Monrovia, was "catastrophic" and "deteriorating daily". They reported that fears of Ebola among staff members and patients had shut down much of the city's health system, leaving many people without medical treatment for other conditions. In a 26 September statement, WHO said, "The Ebola epidemic ravaging parts of West Africa is the most severe acute public health emergency seen in modern times. Never before in recorded history has a
biosafety level four pathogen infected so many people so quickly, over such a broad geographical area, for so long." Intense contact tracing and strict isolation largely prevented further spread of the disease in the countries that had imported cases. , suspected cases and deaths were reported; however, the WHO said that these numbers may be underestimated. Because they work closely with the body fluids of infected patients, healthcare workers were especially vulnerable to infection; in August 2014, the WHO reported that 10% of the dead were healthcare workers. In September 2014, it was estimated that the countries' capacity for treating Ebola patients was insufficient by the equivalent of 2,122 beds; by December there were a sufficient number of beds to treat and isolate all reported Ebola cases, although the uneven distribution of cases was causing serious shortfalls in some areas. On 28 January 2015, the WHO reported that for the first time since the week ending 29 June 2014, there had been fewer than 100 new confirmed cases reported in a week in the three most-affected countries. The response to the epidemic then moved to a second phase, as the focus shifted from slowing transmission to ending the epidemic. On 8 April 2015, the WHO reported only 30 confirmed cases, the lowest weekly total since the third week of May 2014. On 29 December 2015, 42 days after the last person tested negative for a second time, Guinea was declared free of Ebola transmission. At that time, a 90-day period of heightened surveillance was announced by that agency. "This is the first time that all three countries – Guinea, Liberia and Sierra Leone – have stopped the original chains of transmission ...", the organisation stated in a news release. A new case was detected in Sierra Leone on 14 January 2016. However, the outbreak was declared no longer an emergency on 29 March 2016.
2014 spread outside West Africa On 19 September, Eric Duncan flew from his native Liberia to Texas; five days later he began showing symptoms and visited a hospital but was sent home. His condition worsened and he returned to the hospital on 28 September, where he died on 8 October. Health officials confirmed a diagnosis of Ebola on 30 September – the first case in the United States. In early October, Teresa Romero, a 44-year-old Spanish nurse, contracted Ebola after caring for a priest who had been repatriated from West Africa. This was the first transmission of the virus to occur outside Africa. Romero tested negative for the disease on 20 October, suggesting that she may have recovered from Ebola infection. On 12 October, the
Centers for Disease Control and Prevention (CDC) confirmed that a nurse in Texas,
Nina Pham, who had treated Duncan tested positive for the Ebola virus, the first known case of transmission in the United States. On 15 October, a second Texas health-care worker who had treated Duncan was confirmed to have the virus. An unrelated case involved a doctor in New York City, who returned to the United States from Guinea after working with
Médecins Sans Frontières and tested positive for Ebola on 23 October. The person recovered and was discharged from
Bellevue Hospital on 11 November. On 29 December 2014,
Pauline Cafferkey, a British nurse who had just returned to
Glasgow from Sierra Leone, was diagnosed with Ebola at Glasgow's
Gartnavel General Hospital. After initial treatment in Glasgow, she was transferred by air to
RAF Northolt, then to the specialist
high-level isolation unit at the
Royal Free Hospital in
London for longer-term treatment.
2017 Democratic Republic of the Congo On 11 May 2017, the DRC Ministry of Public Health notified the WHO about an outbreak of Ebola. Four people died, and four people survived; five of these eight cases were laboratory-confirmed. A total of 583 contacts were monitored. On 2 July 2017, the WHO declared the end of the outbreak.
2018 Équateur province On 14 May 2018, the World Health Organization reported that "the Democratic Republic of Congo reported 39 suspected, probable or confirmed cases of Ebola between 4 April and 13 May, including 19 deaths." Some 393 people identified as contacts of Ebola patients were being followed up. The outbreak centred on the
Bikoro, Iboko, and
Wangata areas in
Equateur province, On 13 May 2018, WHO Director-General
Tedros Adhanom Ghebreyesus visited Bikoro. Reports emerged that maps of the area were inaccurate, not so much hampering medical providers as
epidemiologists and officials trying to assess the outbreak and containment efforts. The 2018 outbreak in the DRC was declared over on 24 July 2018.
2018–2020 Kivu On 1 August 2018, the world's 10th Ebola outbreak was declared in
North Kivu province of the Democratic Republic of the Congo. It was the first Ebola outbreak in a military conflict zone, with thousands of refugees in the area. By November 2018, nearly 200 Congolese had died of Ebola, about half of them from the city of
Beni, where armed groups are fighting over the region's mineral wealth, impeding medical relief efforts. By March 2019, this became the second largest Ebola outbreak ever recorded, with more than 1,000 cases and insecurity continuing to be the major resistance to providing an adequate response. , the WHO reported 2025 confirmed and probable cases with 1357 deaths. In June 2019, two people died of Ebola in neighbouring
Uganda. In July 2019, an infected man travelled to
Goma, home to more than two million people. One week later, on 17 July 2019, the WHO declared the Ebola outbreak a
global health emergency, the fifth time such a declaration has been made by the organisation. A government spokesman said that half of the Ebola cases are unidentified, and he added that the current outbreak could last up to three years. On 25 June 2020, the second biggest EVD outbreak ever was declared over.
2020 Équateur province On 1 June 2020, the Congolese health ministry announced a new DRC outbreak of Ebola in
Mbandaka,
Équateur Province, a region along the Congo River. Genome sequencing suggests that this outbreak, the 11th outbreak since the virus was first discovered in the country in 1976, is unrelated to the one in North Kivu Province or the previous outbreak in the same area in 2018. It was reported that six cases had been identified; four of the people had died. It is expected that more people will be identified as surveillance activities increase. By 15 June the case count had increased to 17 with 11 deaths, with more than 2,500 people having been vaccinated. The 11th EVD outbreak was officially declared over on 19 November 2020. By the time the Équateur outbreak ended, it had 130 confirmed cases with 75 recoveries and 55 deaths.
2021 North Kivu On 7 February 2021, the Congolese health ministry announced a new case of Ebola near Butembo, North Kivu detected a day before. The case was a 42-year-old woman who had symptoms of Ebola in Biena on 1 February 2021. A few days after, she died in a hospital in Butembo. The WHO said that more than 70 people with contact with the woman had been tracked. On 11 February 2021, another woman who had contact with the previous woman died in the same town, and the number of traced contacts increased to 100. A day after, a third case was detected in Butembo. On 3 May 2021, the 12th EVD outbreak was declared over, resulting in 12 cases and six deaths. Heightened surveillance will continue for 90 days after the declaration, in case of resurgence. On 14 February, the Guinean government declared an Ebola epidemic. The outbreak may have started following reactivation of a
latent case in a survivor of an earlier outbreak. As of 4 May 2021, 23 cases were reported, with no new cases or deaths since 3 April 2021.
Ivory Coast On 14 August 2021, The Ministry of Health of
Cote d’Ivoire confirmed the country's first case of Ebola since 1994. This came after the Institut Pasteur in Cote d'Ivoire confirmed the Ebola Virus Disease in samples collected from a patient, who was hospitalized in the commercial capital of
Abidjan, after arriving from Guinea. However, on 31 August 2021, the WHO found that, after further tests in a laboratory in
Lyon, the patient did not have Ebola. The cause of her disease is still being analyzed.
2022 On 23 April 2022, a case of Ebola was confirmed in the DRC in the Equateur province. The case was a 31-year-old man whose symptoms began on 5 April, but did not seek treatment for over a week. On 21 April, he was admitted to an Ebola treatment centre and died later that day. By 24 May 2022, there were 5 recorded deaths in the DRC. On 15 August, the fifth case was buried, and the outbreak was declared over, 42 days after, on 4 July 2022. In September 2022,
Uganda reported 7 cases infected with the Ebola Sudan strain, but by mid-October the count had increased to 63. In November 2022, the outbreak in Uganda continued — still without a vaccine. ==History==