Ebola Virus Disease in West Africa — The First 9 Months of the Epidemic and Forward Projections

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Ebola superspreading

This chapter gives an overview on the recent outbreak of Ebola Virus Disease in West Africa which has lasted for over seventeen months. The Ebola virus has been implicated as a causative agent of viral haemorrhagic fever occurring in Central Africa over the last thirty-nine years. However, the Ebola virus has not previously been recognised as an endemic virus causing outbreaks of viral illness in West Africa. The start of what was to become the largest Ebola virus disease (EVD) outbreak in known history was first reported to the World Health Organization (WHO) on the 23rd of March 2014 and since then it has transformed into an unprecedented and severe epidemic affecting the three countries of West Africa (Guinea, Liberia and Sierra Leone). The emergence of this lethal virus in a setting of profound poverty, a dysfunctional public-health and a weak government infrastructure alarmed the wider world and caused dread from an uncontrollable spread.

Effectiveness of screening for Ebola at airports

Magnitude of Ebola relative to other causes of death in Liberia, Sierra Leone, and Guinea.

The first epidemic of Ebola haemorrhagic disease in West Africa is the largest and longest Ebola epidemic till date, where the outbreak notably involved three countries with distant spread to other countries. It has caused significant mortality, with reported case fatality rates of up to 70%. Data and relevant information were extracted from the review of majorly relevant publications/papers about the Ebola epidemic in West Africa and other previous outbreaks of Ebola virus (EBOV). As of 2016, with the epidemic under control, the World Health Organization has warned that flare-ups of the disease are likely to continue for some time as recently occurred in Sierra Leone and the on-going in Guinea. As this may not be the last outbreak of Ebola virus disease (EVD) in West Africa, there is a need to focus on diagnostic and research capacity required to curtail EVD with adequate measures for emergency preparedness and policies for innovative treatment strategies.

Ebola virus disease (EVD) is a complex zoonosis that is highly virulent in humans. The largest recorded outbreak of EVD is ongoing in West Africa, outside of its previously reported and predicted niche. We assembled location data on all recorded zoonotic transmission to humans and Ebola virus infection in bats and primates (1976–2014). Using species distribution models, these occurrence data were paired with environmental covariates to predict a zoonotic transmission niche covering 22 countries across Central and West Africa. Vegetation, elevation, temperature, evapotranspiration, and suspected reservoir bat distributions define this relationship. At-risk areas are inhabited by 22 million people; however, the rarity of human outbreaks emphasises the very low probability of transmission to humans. Increasing population sizes and international connectivity by air since the first detection of EVD in 1976 suggest that the dynamics of human-to-human secondary transmission in contemporary outbreaks will be very different to those of the past.DOI: http://dx.doi.org/10.7554/eLife.04395.001

In March 2016, the World Health Organization declared the 2014-15 Ebola virus disease (EVD) outbreak officially over. With around 29 000 cases and 11 000 deaths in 27 months, this EVD outbreak was more than 60 times larger than any before, and unique in its cross-border spread and involvement of urban centres. Local and international responses were slow and initially inadequate, but establishment of the United Nations Mission for Ebola Emergency Response, 9 months after the outbreak began, allowed a coordinated effort that slowed and eventually controlled the spread of disease. Internationally, there were fears that EVD would spread widely beyond Africa, despite reassurances from public health authorities. However, after nurses in the US became infected, public fear and concern for the safety of healthcare workers led to political intervention and varied, sometimes excessive, border controls, quarantine arrangements and hospital preparations. Altogether, fewer than 30 EVD cases were managed in countries outside Africa, all but three of which were acquired in West Africa. In Australia, the Australian Health Protection Principal Committee led the internal response, including enhanced screening of incoming passengers at international airports and development of public health and laboratory testing protocols by expert subcommittees. States and territories nominated designated hospitals to care for EVD patients. Development of EVD infection prevention and control (IPC) guidelines was initially poorly coordinated within and between jurisdictions, often with significant discrepancies, causing confusion and fear among healthcare workers. The Infection Prevention and Control Expert Advisory Group was established to develop national IPC guidelines. There were no confirmed cases in Australia, but investigation of several people with suspected EVD provided valuable experience in use of protocols and high-level containment facilities. The Australian Government was initially reluctant to send aid workers to West Africa, but later contracted a private company to staff and manage a treatment centre in Sierra Leone, which treated 91 patients with EVD during 4 months of operation. Among the lessons learnt for Australia was the need to increase awareness of routine IPC practices in hospitals, where significant deficiencies were exposed, and to maintain a high enough level of preparedness to protect healthcare workers and the public from the next, inevitable, infectious disease emergency.

Commentary on : WHO Ebola Response Team. Ebola virus disease in West Africa—the first 9 months of the epidemic and forward projections. N Engl J Med 2014;371:1481–95.[OpenUrl][1][CrossRef][2][PubMed][3][Web of Science][4] An...

The first cases of the current Ebola virus disease (EVD) outbreak, were seen in Guinea in December 2013 and confirmed three months later as Ebola by World Health Organization (WHO) in March 20141. Since then, the virus has been spreading in an unprecedented manner not only to two neighbouring countries in West Africa namely Liberia and Sierre Leone but also to countries outside of West Africa including Europe and United States, causing widespread fear and hysteria. On August 8, 2014, the WHO declared the Ebola outbreak in West Africa a Public Health Emergency of International Concern (PHEIC) under the International Health Regulations (IHR, 2005)2. This was based on the recommendation of the Emergency Committee which deliberated on the issue during August 6-7, 2014. According to the Emergency Committee, the Ebola outbreak in West Africa constituted an ‘extraordinary event’ and a public health risk to other States; the possible consequences of further international spread are particularly serious in view of the virulence of the virus, the intensive community and health facility transmission patterns, and the weak health systems in the currently affected and most-at-risk populations.

The 2014 outbreak of Ebola virus disease (EVD) in West Africa was the largest ever recorded. Starting in September 2014, International Medical Corps (IMC) managed 5 Ebola treatment units (ETUs) in Liberia and Sierra Leone, which cumulatively cared for about 2,500 patients. We conducted a retrospective cohort study of patient data collected at the 5 ETUs over 1 year of operations. To collect clinical and epidemiological data from the patient care areas, each chart was either manually copied across the fence between the high-risk zone and low-risk zone, imaged across the fence, or imaged in the high-risk zone. Each ETU's data were entered into a separate electronic database, and these were later combined into a single relational database. Lot quality assurance sampling was used to ensure data quality, with reentry of data with high error rates from imaged records. The IMC database contains records on 2,768 patient presentations, including 2,351 patient admissions with full follow-up data. Of the patients admitted, 470 (20.0%) tested positive for EVD, with an overall case fatality ratio (CFR) of 57.0% for EVD-positive patients and 8.1% for EVD-negative patients. Although more men were admitted than women (53.4% vs. 46.6%), a larger proportion of women were diagnosed EVD positive (25.6% vs. 15.2%). Diarrhea, red eyes, contact with an ill person, and funeral attendance were significantly more common in patients with EVD than in those with other diagnoses. Among EVD-positive patients, age was a significant predictor of mortality: the highest CFRs were among children under 5 (89.1%) and adults over 55 (71.4%). While several prior reports have documented the experiences of individual ETUs, this study is the first to present data from multiple ETUs across 2 countries run by the same organization with similar clinical protocols. Our experience demonstrates that even in austere settings under difficult conditions, it is possible for humanitarian organizations to collect high-quality clinical and epidemiologic data during a major infectious disease outbreak.

Perspectives on Ebola

Anticipated Negative Responses by Students to Possible Ebola Virus Outbreak, Guangzhou, China.