History of Ebola

History of Ebola

Ebola Historical and Current Case and Mortality View as of 11 December 2014 

(Data sourced from WHO and CDC)

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Emergence of the Virus - Nzara and Maridi, South Sudan, 1976

The first case of Ebola-Sudan (EBO-S) was first detected in Nzara, Sudan and then spread to Maridi, Tembura, and Juba. On June 27, 1976, a Nzara Cotton Manufacturing Factory cloth room worker, YuG, became ill with a hemorrhagic febrile disease, Ebola hemorrhagic fever (EHF), and died in the Nzara hospital on July 6, 1976. The second primary case of EHF was a man, Bz, who also worked in the cloth room and died in the hospital on July 14. Bz's wife, who nursed him during his illness, suffered a fatal case of Ebola hemorrhagic fever. The epidemiologically most important primary case, PG, who worked alongside YuG and Bz, became ill on July 18 and died on July 27 after several short stays in the Nzara hospital. 69% of all the EHF cases in Nzara and the introduction to Maridi and Tembura were traced to PG. The World Health Organisation (WHO) investigators reported observing direct person-to-person transmission of EBO-S through six generations of EHF cases traced back to PG.

 

Yambuku Region 1976

Between 1 September and 24 October 1976, a number of further cases of acute viral haemorrhagic fever occurred in Yambuku in the Democratic Republic of Congo. The outbreak was centred in the Bumba Zone of the Equateur Region and most of the cases were recorded within a radius of 70 km of Yambuku, although a few patients sought medical attention in Bumba, Abumombazi, and the capital city of Kinshasa, where individual secondary and tertiary cases occurred. The 88% Mortality rate was attributed to it being a new disease and medical personnel not knowing how to contain and treat it.

 

The disease was spread by close personal contact and by use of contaminated needles and syringes in hospitals/clinics.

 

Tandala, Zaire, 1977

 

The Ebola virus was recovered from a nine-year-old girl who died of acute hemorrhagic fever in June 1977 at Tandala Hospital in north-western Zaire, in the first reported recognised case of this disease since the discovery epidemics of 1976 in Zaire and Sudan.

 

Nzara, South Sudan, 1979

 

In early August 1979, with Sudan in the throes of an escalating civil war, Ebola struck again in Nzara and spread rapidly. The index case, again, was that of a worker in a cotton factory who succumbed at Nzara hospital on August 2. Again, the area was virtually cordoned off from the rest of the country. The World Health Organisation (WHO) was notified in mid-September, and an expert arrived in Nzara on September 22. He found that the disease struck suddenly and without any warning, with patients complaining of terrible headaches and weakness. Within days, their condition worsened-chills, high fevers (over 105°F), severe muscle and joint pains, and throats so sore that they had trouble swallowing saliva, let alone any food. Around the fourth day, the patients began hemorrhaging from various extremities. When death came, it was due to shock on account of fluid loss. Once again, it appeared that the hospital was the centre of the outbreak and the experts had a hard time convincing people to bring their Ebola patients and victims there.

 

Mekouka, Gabon and Tai Forest, Ivory Coast, 1994

 

The disease was not reported again until the end of 1994 when three outbreaks occurred within a relatively short time.

 

In October 1994, an outbreak was identified in a chimpanzee study group in Tai National Park, Ivory Coast. An ethnologist became ill after autopsying a chimpanzee found dead in the Tai forest. It was the first and only human case observed in West Africa, and the only case clearly attributed to Ebola sub-type E. Ivory Coast. 25% of the 43 chimpanzees in the studied community were recorded to have died from the virus.

 

Number of cases we reported the following month in north-east Gabon in the gold panning camps of Meouka, Andock, and Minkebe.

 

Kikwit, Democratic Republic of Congo, 1994

 

Between January and June 1995, the town of Kikwit, Democratic Republic of Congo (DRC), and its surroundings were the epicenter of a severe outbreak of Ebola (EBO) hemorrhagic fever (EHF) that affected hundreds of people. The epidemic occurred during a lengthy political transition in DRC that was characterized by the interruption of international cooperation, inadequate disease surveillance and reporting, and a breakdown of the general health care infrastructure, due in part to a lack of motivation among poorly paid health personnel.

 

Mayibout and Booué, Gabon, 1996

 

Early February 1996, a number of cases from Mayibout were admitted to Makoukou provincial hospital showing signs of EHF (high fever, bloody diarrhoea, and severely reddened eyes). The average age of the 19 original patients was 18 years. Rapid identification and the implementation of appropriate control measures brought the outbreak quickly under control and prevented further amplification. The outbreak was officially declared over by the WHO (World Health Organisation) on 23 April 1996; 42 days (twice the incubation period) after the last EHF patient death.

 

The first case in the Booué area  occurred on 23 July 1996. The index case was a 39-year-old hunter who lived in a forest camp in the Booué area. He died on August 7. The second case was a close friend of the index case and died in August. The third and the fourth cases of EHF (also fatal) occurred in late September and were in a traditional healer and his assistant who treated the healer. During the beginning of the outbreak, a dead chimpanzee was found in the forest and tested positive for Ebola. On October 18, three of four new cases were in children who had been in close contact with previous EHF cases. The outbreak was brought under control by the international team by 13 November 1996. WHO officially declared this outbreak over on 2 March 1997.

 

Gulu , Uganda, 2000

 

An outbreak of Ebola disease was reported from Gulu district, Uganda, on 8 October 2000. The outbreak was characterised by fever and haemorrhagic manifestations, and affected health workers and the general population of Rwot-Obillo, a village 14 km north of Gulu town. Later, the outbreak spread to other parts of the country including Mbarara and Masindi districts. Response measures included surveillance, community mobilisation, case and logistics management. The international response was coordinated by the World Health Organisation (WHO) under the umbrella organisation of the Global Outbreak and Alert Response Network.

 

At this time, a WHO/CDC case definition for Ebola was adapted and used to capture four categories of cases, namely, the 'alert', 'suspected', 'probable' and 'confirmed cases'.

 

Guidelines for identification and management of cases were developed and disseminated to all persons responsible for surveillance, case management, contact tracing and Information Education Communication (IEC). For the duration of the epidemic that lasted up to 16 January 2001, a total of 425 cases with 224 deaths were reported countrywide.

 

Community mobilisation using community-based resource persons and political organs, such as Members of Parliament was effective in getting information to the public. This was critical in controlling the epidemic.

 

Libreville, Gabon, 2001

 

WHO initially received reports of 12 suspected cases, including 10 deaths from haemorrhagic fever in early December 2001. At the end of this outbreak, 97 deaths from Ebola were reported.

 

Mbomo, Republic of Congo, 2002 and 2003

 

An Ebola outbreak was reported from the Mbomo or Kéllé regions (Congo-Brazzaville), in the north of the country, that were suspected as points of origin.

 

The response to the Ebola outbreak started in the first week of January 2002, after reports of Ebola-related deaths in a small village on the border with Gabon in the Région de la Cuvette.

 

Assessments were carried out in Mbomo and later in Kéllé following reports of a new chain of infection. Lack of epidemiological data and surveillance made it difficult to chart out the full course and extent of the epidemic.

 

Efforts to stop the chains of Ebola infection for both years  were severely hampered by the extreme remoteness of villages, reluctance of the affected pygmy communities to be isolated and the shortage of experienced international and local health care workers to manage cases of Ebola infections.

 

Yambio, South Sudan, 2004

 

In May and June 2004, the WHO reported 30 cases with 12 deaths. But on Jun 22 the agency revised 12 cases, including one death, had been reclassified as measles. The count of 17 cases with 7 deaths signalled a case-fatality rate of 41%, as compared with 50% to 90% in past Ebola outbreaks.

 

The Sudan subtype of Ebola virus was confirmed in tests by the Kenya Medical Research Institute and the US Centers for Disease Control and Prevention, the WHO said. The agency worked with local health authorities, UNICEF, Medicins Sans Frontieres-France, other non-governmental organisations, and churches to control the outbreak.

 

Bundibugyo, Uganda and Kasai, Democratic Republic of Congo, 2007

 

During August 2007-February 2008, a new strain, Bundibugyo Ebolavirus species was identified during an outbreak of Ebola viral hemorrhagic fever in Bundibugyo district, western Uganda. The species Bundibugyo Ebolavirus  is closely related to the infamous Ebola virus.

 

Twelve years after the Kikwit Ebola outbreak in 1995, Ebola virus re-emerged in the Kasaï-Occidental province of the Democratic Republic of Congo (DRC) between May and November 2007, affecting more than 260 humans and causing 186 deaths.

 

The local populations reported no unusual morbidity or mortality among wild or domestic animals, but they described a massive annual fruit bat migration toward the southeast, up the Lulua River. Migrating bats settled in the outbreak area for several weeks, between April and May, nestling in the numerous fruit trees in Ndongo and Koumelele islands as well as in palm trees of a largely abandoned plantation. They were massively hunted by villagers, for whom they represented a major source of protein. Researchers were able to link the suspected role of bats in the natural cycle of Ebola virus and indicate that the massive seasonal fruit bat migrations should be taken into account in operational Ebola risk maps and seasonal alerts in the DRC.

 

Philippines, 2008

 

The 2008 Reston Ebolavirus strain infection event in domestic pigs triggered continued epidemiologic investigations among Philippine health and veterinary agencies in collaboration with international filovirus experts. Prior to this, there were only 3 known and documented Reston Ebolavirus outbreaks in nonhuman primates in the world, all traced back to a single geographic source in the Philippines in a monkey breeding/export facility. The first one in 1989 was the first-ever Ebola virus that emerged outside of Africa and was also the first known natural infection of Ebola virus in nonhuman primates. When it was first discovered among laboratory monkeys in the United States, the source was immediately traced back to a pig farm located in the Philippines.

 

Six workers from the pig farm and slaughterhouse developed antibodies but did not become sick.

 

The Philippines is still the only known geographic source of Reston Ebolavirus (REBOV).

 

Democratic Republic of Congo, 2008 and 2009

 

The Ebola outbreak in Mweka district in Kasai-Occidental (West Kasai) province was first reported on Dec 26 of 2008.

 

The Ministry of Health of the Democratic Republic of the Congo (DRC), on 16 February 2009 declared the end of the Ebola epidemic in the Mweka and Luebo health zones in the Province of Kasai Occidental . The last person to be infected by the virus died on 1 January 2009. This is more than double the maximum incubation period (42 days) for Ebola.

 

Kibaale District, Uganda and Isiro Health Zone, Dem. Rep. Congo, 2012

 

In July 2012, an outbreak of Ebola virus disease was reported in Kagadi in the Kibaale District with a 66% case fatality rate, bringing back memories of the 2000 Uganda Ebola outbreak. Officials urged people not to panic, and a national emergency task force was established. The government, World Health Organisation and U.S. Centers for Disease Control and Prevention sent experts to tackle the outbreak.

 

In August 2012, the Ministry of Health (MoH) of the Democratic Republic of Congo (DRC) notified the World Health Organisation (WHO) of an outbreak of Ebola haemorrhagic fever in the Isiro and Dungu Health Zones of Province Orientale in Eastern DRC.

 

Laboratory investigations conducted at the Uganda Virus Research Institute (UVRI), Entebbe, Uganda, confirmed Ebola virus (Bundibugyo species).

 

For updates on the 2014 outbreak, please see Healix's latest updates or information on the Ebola Outbreak of 2014.