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2014-2016 Ebola Outbreak in West Africa

On March 23, 2014, the World Health Organization (WHO) reported cases of Ebola Virus Disease (EVD) in the forested rural region of southeastern Guinea. The identification of these early cases marked the beginning of the West Africa Ebola epidemic, the largest in history.

Summary

The initial case, or index patient, was reported in December 2013. An 18-month-old boy from a small village in Guinea is believed to have been infected by bats. After five additional cases of fatal diarrhea occurred in that area, an official medical alert was issued on January 24, 2014, to the district health officials. The Ebola virus soon spread to Guinea’s capital city of Conakry, and on March 13, 2014, the Ministry of Health in Guinea issued an alert for an unidentified illness. Shortly after, the Pasteur Institute in France confirmed the illness as EVD caused by Zaire ebolavirus. On March 23, 2014, with 49 confirmed cases and 29 deaths, the WHO officially declared an outbreak of EVD.

Weak surveillance systems and poor public health infrastructure contributed to the difficulty surrounding the containment of this outbreak and it quickly spread to Guinea’s bordering countries, Liberia and Sierra Leone. By July 2014, the outbreak spread to the capitals of all three countries. This was the first time EVD extended out from more isolated, rural areas and into densely populated urban centers, providing an unprecedented opportunity for transmission.

On August 8, 2014, WHO declared the deteriorating situation in West Africa a Public Health Emergency of International Concern (PHEIC), which is designated only for events with a risk of potential international spread or that require a coordinated international response. Over the duration of the epidemic, EVD spread to seven more countries: Italy, Mali, Nigeria, Senegal, Spain, the United Kingdom, and the United States. Later secondary infection, mainly in a healthcare setting, occurred in Italy, Mali, Nigeria, and the United States.

The scope of this outbreak, both in terms of cases and geography, can be attributed to the unprecedented circulation of EVD into crowded urban areas, increased mobilization across borders, and conflicts between key infection control practices and prevailing cultural and traditional practices in West Africa. Engaging local leaders in prevention programs and messaging, along with careful policy implementation at the national and global level, helped to eventually contain the spread of the virus and put an end to this outbreak.

Liberia was first declared Ebola-free in May 2014. Additional cases were found and treated, and the country was again declared Ebola-free in September 2015. After this, more cases were discovered again, until finally on January 14, 2016, Liberia announced it was Ebola-free and no additional cases have been detected since.

After an initial declaration in November 2015, Sierra Leone announced it was Ebola-free on March 7, 2016. A preliminary statement in December 2015 was retracted when additional cases were discovered in March and April and Guinea was finally declared Ebola-free in June 2016.[1] Two and a half years after the first case was discovered, the outbreak ended with more than 28,600 cases and 11,325 deaths.

Ebola in the United States

Overall, eleven people were treated for Ebola in the United States during the 2014-2016 epidemic. On September 30, 2014, CDC confirmed the first travel-associated case of EVD diagnosed in the United States in a man who traveled from West Africa to Dallas, Texas. The patient (the index case) died on October 8, 2014. Two healthcare workers who cared for him in Dallas tested positive for EVD. Both recovered.

On October 23, 2014, a medical aid worker who had volunteered in Guinea was hospitalized in New York City with suspected EVD. The diagnosis was confirmed by the CDC the next day. The patient recovered.

Seven other people were cared for in the United States after they were exposed to the virus and became ill while in West Africa, the majority of whom were medical workers. They were transported by chartered aircraft from West Africa to hospitals in the United States. Six of these patients recovered, one died.[2]

CDC Response

CDC activated its Emergency Operations Center in July 2014 to help coordinate technical assistance and disease control activities with partners. CDC personnel deployed to West Africa to assist with response efforts, including surveillance, contact tracing, data management, laboratory testing, and health education. CDC staff also provided support with logistics, staffing, communication, analytics, and management.

To prevent cross-border transmission, travelers leaving West Africa were screened at airports. Exit screening helped identify those at risk for EVD and prevent the spread of the disease to other countries. The United States also implemented enhanced entry screening for travelers coming from Guinea, Liberia, Sierra Leone, and Mali by routing them to designated airports better able to assess travelers for risk.[3]

During the height of the response, CDC trained 24,655 healthcare workers in West Africa on infection prevention and control practices.[4] In the United States, more than 6,500 people were trained during live training events throughout the response. In addition, laboratory capacity was expanded in Guinea, Liberia, and Sierra Leone with 24 laboratories able to test for Ebola virus by the end of 2015.[5]

Impact

On March 29, 2016, the WHO lifted the PHEIC status on West Africa’s Ebola situation. The impact this epidemic had on the world, and particularly West Africa, is significant. A total of 28,616 cases of EVD and 11,310 deaths were reported in Guinea, Liberia, and Sierra Leone. There were an additional 36 cases and 15 deaths that occurred when the outbreak spread outside of these three countries. The table below shows the distribution of cases and deaths in countries with widespread transmission and countries affected by the epidemic.

Countries with Widespread Transmission and other Countries Affected During the Epidemic

Country Total Cases (Suspected, Probable, Confirmed) Laboratory Confirmed Cases Total Deaths
Countries with Widespread Transmission
Guinea 3,814 3,358 2,544
Liberia 10,678 3,163 4,810
Sierra Leone 14,124 8,706 3,956
Affected Countries
Italy 1 1 0
Mali 8 7 6
Nigeria 20 19 8
Senegal 1 1 0
Spain 1 1 0
United Kingdom 1 1 0
United States 4* 4 1
Total 28,652 15,261 11,325

* While there were 11 patients with EVD in total treated in the United States, only four patients became ill after they arrived in the United States, either after exposure in West Africa or in a healthcare setting.


Graphs of reported cases, called epidemic curves, show the rate (incidence) of new, probable, and confirmed cases over the duration of the outbreak in the three West African countries with widespread transmission, Guinea, Liberia, and Sierra Leone.

Healthcare workers caring for patients with EVD were among those at highest risk for contracting the disease. During the epidemic, Liberia lost 8% of its doctors, nurses, and midwives to EVD.[6] In addition to the devastating effects on the healthcare workforce in Guinea, Liberia, and Sierra Leone, the Ebola epidemic severely impacted the provision of healthcare services and caused setbacks in the treatment and control of HIV, tuberculosis, measles, and malaria in these countries.[7]

The epidemic also had a great impact on children. Nearly 20% of all EVD cases occurred in children under 15 years of age, and an estimated 30,000 children became orphans during this epidemic. As funding and logistics previously dedicated to child vaccination campaigns were redirected to Ebola response or postponed to avoid public gatherings, routine immunizations decreased by 30%, further putting children at risk of getting vaccine-preventable diseases.[8],[9]

The epidemic has been estimated to cost a total of $4.3 billion USD.[10] Investments in Guinea, Liberia, and Sierra Leone dramatically decreased. Similarly, the  countries experienced a substantial loss in private sector growth, decline in agricultural production leading to concerns about food security, and a decrease in cross-border trade as restrictions on movements, goods, and services increased.[11],[12],[13]

Current Guidance

While the spread of EVD in West Africa has been controlled, additional cases may continue to occur from time to time. However, because of ongoing surveillance and strengthened response capabilities, the affected countries now have the experience and tools to rapidly identify cases and limit the spread of the disease.

CDC no longer recommends that U.S. residents avoid nonessential travel to Guinea, Liberia, or Sierra Leone. Although there is believed to be no risk of EVD to travelers in these countries, travelers should, as usual, avoid contact with sick people, dead bodies, or blood and body fluids.

References

[1] Kaner J, Schaak S.  Understanding Ebola: the 2014 Epidemic [PDF – 486KB]Globalization and Health (2016) 12:53.

[2] Bell BP, Damon IK, Jernigan DB et al. Overview, Control Strategies, and Lessons Learned in the CDC Response to the 2014–2016 Ebola Epidemic. Morbidity and Mortality Weekly Report. 2016;65(3):4-11.

[3] CDC – Division of Global Migration and Quarantine – International Border Team.

[4] CDC – International Infection Control Team.

[5] 2015. Ebola labs testing in infected African countries. February 20. Accessed January 20, 2016.

[6] David K Evansa, Markus Goldstein, Anna Popova. 2015. “Health-care worker mortality and the legacy of the Ebola epidemic.” The Lancet Global Health 3 (8): e439–e440. Accessed December 22, 2015. doi:10.1016/S2214-109X(15)00065-0.

[7] Parpia, A. S., Ndeffo-Mbah, M. L., Wenzel, N. S., & Galvani, A. P. (2016). Effects of Response to 2014–2015 Ebola Outbreak on Deaths from Malaria, HIV/AIDS, and Tuberculosis, West Africa. Emerging Infectious Diseases, 22(3), 433-441.

[8] UNDP. 2014. “Assessing the socio-economic impacts of Ebola Virus Disease in Guinea, Liberia and Sierra Leone: The Road to Recovery” [PDF – 1.8MB] Accessed December 22, 2015.

[9] Kaner J, Schaak S.  Understanding Ebola: the 2014 Epidemic [PDF – 486KB]Globalization and Health (2016) 12:53.

[10] Wright S, Hanna L, Malifert M. A wake-up call:  lessons from Ebola for the World Health Systems [PDF – 1.73MB].  Save the children. 2015.

[11] The World Bank. 2015. Summary on the Ebola Recovery Plan: Sierra Leone. April 15. Accessed January 20, 2016.

[12] The World Bank. 2015. Summary on the Ebola Recovery Plan: Guinea. April 16. Accessed January 20, 2016.

[13] The World Bank. 2015. Summary on the Ebola Recovery Plan: Liberia – Economic Stabilization and Recovery Plan (ESRP). April 15. Accessed January 20, 2016.

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