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2014 Ebola Outbreak in West Africa Epidemic Curves

On March 23, 2014, the World Health Organization (WHO) reported the first cases of EVD in West Africa in what would become the largest Ebola virus epidemic in history. Over two years, a total of 28,616 cases of EVD and 11,310 deaths were reported in Guinea, Liberia, and Sierra Leone. An additional 36 cases and 15 deaths occurred when the outbreak spread outside these three countries.

The following graphs demonstrate the incidence of newly suspected, probable, and confirmed cases over the duration of the epidemic in Guinea, Liberia, and Sierra Leone, the countries most impacted by the epidemic, both in the aggregate and separated by country.

The Frequency of New Cases in Guinea, Liberia, and Sierra Leone during the Ebola Outbreak from March 25, 2014 to April 13, 2016

Epi Graph-1: The Frequency of New Cases in Guinea, Liberia, and Sierra Leone during the Ebola Outbreak from March 25, 2014 to April 13, 2016

Graph 1: Case Incidence in Guinea, Liberia, and Sierra Leone.

This graph shows the frequency of newly reported cases in Guinea, Liberia, and Sierra Leone provided in WHO Situation Reports beginning on March 25, 2014, through the last situation report on June 10, 2016. The numbers are a total of suspected, probable, and confirmed cases.

Table 1: Case Incidence in Guinea, Liberia, and Sierra Leone.
Date Number of Cases per Month
3/31/2014 120
4/30/2014 114
5/28/2014 75
6/24/2014 290
7/31/2014 723
8/28/2014 1730
9/26/2014 3501
10/31/2014 6987
11/28/2014 3559
12/31/2014 3272
1/28/2015 1886
2/25/2015 1637
3/31/2015 1484
4/29/2015 1120
5/31/2015 847
6/30/2015 395
7/31/2015 300
8/31/2015 225
9/29/2015 323
10/30/2015 159
11/30/2015 54
12/30/2015 0
1/27/2016 2
2/17/2016 0
3/30/2016 7
4/13/2016 6

The Frequency of New Cases in Guinea during the Ebola Outbreak from March 25, 2014 to April 13, 2016

Graph 2: Case Incidence in Guinea. This graph shows the frequency of newly reported cases in Guinea provided in WHO Situation Reports beginning on March 25, 2014, through the last situation report on June 10, 2016. The numbers are a total of suspected, probable, and confirmed cases.

Graph 2: Case Incidence in Guinea.

This graph shows the frequency of newly reported cases in Guinea provided in WHO Situation Reports beginning on March 25, 2014, through the last situation report on June 10, 2016. The numbers are a total of suspected, probable, and confirmed cases.

Table 2: Case Incidence in Guinea. 
Date Number of Cases per Month
3/31/2014 112
4/30/2014 109
5/28/2014 60
6/24/2014 109
7/31/2014 70
8/28/2014 188
9/26/2014 426
10/31/2014 593
11/28/2014 488
12/31/2014 552
1/28/2015 210
2/25/2015 238
3/31/2015 337
4/29/2015 86
5/31/2015 74
6/30/2015 93
7/31/2015 36
8/31/2015 9
9/29/2015 15
10/30/2015 3
11/30/2015 0
12/30/2015 0
1/27/2016 0
2/17/2016 0
3/30/2016 7
4/13/2016 3

The Frequency of New Cases in Liberia during the Ebola Outbreak from March 25, 2016 to April 13, 2016

Graph 3: Case Incidence in Liberia. This graph shows the frequency of newly reported cases in Liberia provided in WHO Situation Reports beginning on March 25, 2014, through the last situation report on June 10, 2016. The numbers are a total of suspected, probable, and confirmed cases.

Graph 3: Case Incidence in Liberia.

This graph shows the frequency of newly reported cases in Liberia provided in WHO Situation Reports beginning on March 25, 2014, through the last situation report on June 10, 2016. The numbers are a total of suspected, probable, and confirmed cases.

Table 3: Case Incidence in Liberia
Date Number of Cases per Month
3/31/2014 8
4/30/2014 5
5/28/2014 0
6/24/2014 39
7/31/2014 278
8/28/2014 1049
9/26/2014 2080
10/31/2014 3077
11/28/2014 1100
12/31/2014 383
1/28/2015 604
2/25/2015 616
3/31/2015 474
4/29/2015 610
5/31/2015 344
6/30/2015 0
7/31/2015 6
8/31/2015 0
9/29/2015 0
10/30/2015 0
11/30/2015 3
12/30/2015 0
1/27/2016 0
2/17/2016 0
3/30/2016 0
4/13/2016 3

The Frequency of New Cases in Sierra Leone during the Ebola Outbreak from March 25, 2014 to April 13, 2016

Graph 4: Case Incidence in Sierra Leone. This graph shows the frequency of newly reported cases in Sierra Leone provided in WHO Situation Reports beginning on March 25, 2014, through the last situation report on June 10, 2016. The numbers are a total of suspected, probable, and confirmed cases.

Graph 4: Case Incidence in Sierra Leone.

This graph shows the frequency of newly reported cases in Sierra Leone provided in WHO Situation Reports beginning on March 25, 2014, through the last situation report on June 10, 2016. The numbers are a total of suspected, probable, and confirmed cases.

Table 4: Case Incidence in Sierra Leone
Date Number of Cases per Month
3/31/2014 0
4/30/2014 0
5/28/2014 16
6/24/2014 142
7/31/2014 375
8/28/2014 493
9/26/2014 995
10/31/2014 3317
11/28/2014 1771
12/31/2014 2337
1/28/2015 1072
2/25/2015 783
3/31/2015 673
4/29/2015 424
5/31/2015 429
6/30/2015 302
7/31/2015 258
8/31/2015 216
9/29/2015 308
10/30/2015 156
11/30/2015 55
12/30/2015 0
1/27/2016 2
2/17/2016 0
3/30/2016 0
4/13/2016 0

The dramatic variation in number of cases reported from the end of October to the beginning of November 2014 is due to a change in the data sources used. Prior to October 2014, the cumulative total numbers were derived from a combination of patient databases and country situation reports. Later, the revised approach used numbers compiled by the Ministries of Health and WHO country offices.

Detailed Table of the Case Counts.

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