Ebola has been in existence in Africa, since 1976. Over the past 40 years, sporadic Ebola Virus Disease (EVD) occurred in the Central Africa region.
1976
• 2 Outbreaks occurred simultaneously in Southern Sudan and the Northern DRC (then Zaire).
Sudan
It occurred in Nzara town and was linked to an index case that worked in a cotton factory. Outbreak lasted from June till November. 284 cases were recorded with a fatality case of 53%.
Northern Democratic Republic of Congo
September, 1976: Yambuku, located 800km from Nzara had the outbreak.318 cases were reported in just 2 months. It became the 2nd highest case fatality rate in history (88%). 27% of the cases received injections at Yambuku Hospital. 11% of the health workers died of EVD during the outbreak.
1977
• Prior to the initial outbreak, 9 year old girl in Tandala village was retrospectively diagnosed in the DRC was reported. This recognition led to further investigations, resulting in 7% of seropositive villagers.
1979
July – October
Sudan: Another outbreak of EVD in Yambio ( 25km from Nzara). There were 34 affected individuals with the case fatality of 65%. Index case for this outbreak was linked to the Cotton factory in Nzara. Propensity of the virus spread was noted in hospital setting and close family contact was noted.
1994
A yellow fever outbreak was diagnosed retrospectively. EVD emerged after apparent quiescent period of almost 15 years.
34 years old Swiss ethologist was diagnosed of Ebola. He was working in the Tai National Park ( Cote d’Ivoire) studying chimpanzees.
November, 1994
Massive die offs of chimpanzees occurred. Necropsy was used for the cause ofdeath determination. Aweek after, a team of 3 researchers fell ill. Cause of thisillnesswas liked to a novel virus-the TAFV ( Tai Febrile virus; a subsidiary of Ebola).
Since 1994, almost annual reports of EVD has bee made.
Gabon
4 confirmed EVD case fatality of 82%. It seemed to have originated in North East Gabon, gold panning camps. 52 cases with 31 deaths were reported.
1996
This was the second outbreak in North East Gabon linked to the slaughtering of a dead chimpanzees the forest. 37 confirmed human cases occurred with 21 fatalities
Mid 1996 – 3rd Epidemic
60 cases with 74 fatality rate. Index case was a forest hunter which coincided with the die offs of the chimpazees.
2001-2002
This is the most recent episode in Gabon. The Ogooue –Ivado province in NE Garbon. The outbreak spilled over to adjacent Republic Congo. A total of 122 cases was reported from the 2 countries. A total of 96 deaths with 79% case fatality rate occurred.
During this period, abnormally high levels of animals were found dead including great apes and monkeys in the forest.
Democratic Republic of Congo
Apart from the 1976 and 1979 outbreaks, 5 other EVDs have occurred between 1995 – 2014. One of the largest and the deadliest was Kikwit in 1995. Janurary to July, 315 cases, with 350 dearths; 80 healthworkers were involved. Occurred in communities that were ill served from the basic healthcare staff shortage.
12 years after, (2007 -2008), Kasai Occidental Province of DRC became an EVD site.
2000
Outbreaks reported at Congo and Uganda. It was the largest outbreak before 2014 was in the north Central Uganda, Gulu district from 2001- 2002 caused by the Sudan Virus. 425 cases with a lower case fatality rate 53%.
Major risk factor during the outbreaks was an attendance and participation at burial ceremonies. Health workers were at the particular risk.
2001 – 2003
3 highly fatal EVD outbreaks were reported in the republic of Congo. The average case fatality rate during the outbreaks exceeded 80% and included the most fatal outbreaks to date ( Case fatality of 89%). 128 deaths occurred in 143 cases.
2007
The first occurrence in a milder outbreak of EVD. 149 cases occurred in the Western Uganda.
2011
3 additional small outbreaks .
2012
DRC, There occurred a specie of EVD the BDBV. There were 36 confirmed cases
2014 – Before 2014, EVD outbreaks characterized with its occurrence as random in nature.
March,2014
WHO declared EVD emergence in Guinea. This was going to be the most sizeable , fatal EVD Outbreak in West Africa and protracted outbreaks of EVD in recorded history.
May, 2014
It spread to Kenema and Kenabus in Sierra Loene. A total of 18464 suspected cases with 11699 confirmed cases associated with 6841 deaths have been recorded. Guinea, Liberia, Sierra Loene. Outbreak originated from Guinea, and the brunt was bore by Sierra Loene, accounting for nearly 90% of the cases up till date.
July, 2014
9 cases were identified with a case index as a Liberian Air flier. He denied having contact with other persons with Ebola and claimed to have Malaria. He had vomitted on the flight to Lagos, and he was driven to a private hospital. The cases attended to him unprotected.
August, 2014
A second outbreak occurred at Port Harcourt, Nigeria's oil hub, when on August 1st, a close contact of the Lagos index patient arrived by plane and sought help from a private doctor. The doctor developed symptoms 9 days later and died of Ebola on August 23rd. When the Nigerian authorities, with help from WHO, studied the contacts involved, they discovered an alarming number of high and very high-risk exposures for hundreds of people. It was clear that all required resources had to be mobilized immediately to stop the outbreak.
DRC
WHO announced an outbreak of EVD in Equateur Province in DRC. It was declared an international public health emergency; called for intensified multinationals supports. Called for the containment of the outbreak.
Index case for the outbreak was a two year old child, who died on the 6th day of December. Several family members and a number of Health workers had contact with the family. One of the affected health workers triggered the spread of at least 3 districts of Guinea. The outbreak was fueled by socioeconomic factors.
Dr. Magaret Chan says the fuel is Poverty.
November,2014
It entailed 66 cases. Outbreaks was epidemiologically, virologically unrelated to the EVDs in Guinea and that of Liberia. The toll on healthcare workers in the EVD outbreak has been substantial, as they account for 11 of the 20 EVD cases in Nigeria. Past EVD outbreaks have been amplified in healthcare settings, in West Africa, about 5% of the total number of reported EVD cases being healthcare workers based on data available as of 1 October 2014 .
Resulting Positive Control Measures and Lessons to learnt
Fortunately, past experience with the Zaire Ebolavirus strain also indicates that early, intense and sustained infection control measures in healthcare settings can substantially reduce the size and geographical scope of EVD outbreaks, which is consistent with the recent Nigerian experience. The number of secondary cases decreased over subsequent disease generations in Nigeria, reflecting the effects of interventions, in particular;
• the intense and rapid contact tracing strategy,
• the continuous surveillance of potential contacts,
• communication with the public,
• and the largely effective isolation of infectious individuals. Indeed, the mean reproduction number among secondary cases in Nigeria (i.e. excluding the contribution from the imported traveller) was 0.4 in the presence of control interventions.
The intense and rapid contact tracing strategy was achieved with the help of WHO, the US Centers for Disease Control and Prevention (CDC) and other organizations, the Nigerian authorities was able to reach 100% of known contacts in Lagos and 99.8% in Port Harcourt.
Prompt set-up of isolation, treatment and real-time reporting systems
Another important feature of Nigeria's success was that of the federal and state governments very quickly provided financial and material resources, and well-trained and experienced staff. Isolation wards were immediately set up in most tertiary centres and designated as Ebola treatment Centres. Vehicles and specially adapted mobile communications systems were made available and greatly assisted real-time reporting of the changing situation. All identified contacts were monitored on a daily basis for the maximum incubation period of Ebola - 21 days. A few contacts did try to escape during the surveillance period, but they were tracked and special intervention teams returned them to complete the required monitoring.
Communication with the general public
The Nigerian authorities were quick to put out messages to the general public, the idea being that this would get communities to support the containment measures. Various initiatives put out messages and key facts about Ebola on different media was available. House-to-house and local radio campaigns - using local dialects - explained the risks, how to take personal preventive measures and what was being done to control virus spread.
The Nigerian experience offers a critically important lesson to countries in the region not yet affected by the EVD epidemic, as well as to countries in other regions of the world that risk importation of EVD and that must remain vigilant. As a case in point, the recent importation of an EVD case in the United States from Liberia proves that no country is immune to the risk of EVD in a globally connected world, but that rapid case identification and forceful interventions can stop transmission.
