10 Oct 2014 - Epidemiological update of Ebola Virus Disease in West Africa
Chronology of events – key dates
22 March 2014: the Guinea Ministry of Health notified WHO
about a rapidly evolving outbreak of EVD [1]. The first cases occurred in
December 2013. The outbreak is caused by a clade of Zaïre ebolavirus that is
related but distinct from the viruses that have been isolated from previous
outbreaks in central Africa, and clearly distinct from the Taï Forest ebolavirus
that was isolated in Côte d’Ivoire from 1994–1995 [2-4]. The first cases were
reported from south-eastern Guinea and the capital Conakry.
Figure 2. Distribution of cases of EVD by week of reporting in the three countries with widespread and intense transmission as of week 41 2014, n= 8 011*
Figure 3. Distribution of cases of EVD by week of reporting in Guinea, Sierra Leone, Liberia and Nigeria (as of week 40/2014)
References
May 2014: the first cases were reported from Sierra Leone
and Liberia [5,6] to where the disease is assumed to have spread through the
movement of infected people over land borders.
End of July 2014: a symptomatic case travelled by air to
Lagos, Nigeria, where he infected a number of healthcare workers and airport
contacts before his condition was recognised to be EVD.
8 August 2014: WHO declared the outbreak a Public Health
Event of International Concern (PHEIC) [7] and confirmed on 22 September that
the 2014 Ebola outbreak in West Africa continued to constitute a Public Health
Emergency of International Concern.
29 August 2014: the Ministry of Health in Senegal reported a
confirmed imported case of EVD in a 21-year-old male native of Guinea.
18 September 2014: the United Nations Security Council
recognised the EVD outbreak as a 'threat to international peace and security'
and unanimously adopted a resolution on the establishment of an UN-wide
initiative which focuses assets of all relevant UN agencies to tackle the crisis
[8].
23 September 2014: A study published by the WHO Ebola
response team forecasted more than 20 000 cases (5740 in Guinea, 9890 in
Liberia, and 5000 in Sierra Leone) by the beginning of November 2014 [9]. The
same study estimated the doubling time of the epidemic at 15.7 days in Guinea,
23.6 days in Liberia, and 30.2 days in Sierra Leone.
30 September 2014: the US Centers for Disease Control and
Prevention (CDC) announced the first imported case in US of Ebola linked to the
current outbreak in West Africa.
3 October 2014: In Senegal, all contacts of the imported EVD
case have completed a 21-day follow-up period. No local transmission of EVD has
been reported in Senegal.
6 October 2014: The Spanish authorities reported a confirmed
case of Ebola virus disease (EVD) of a healthcare worker who participated in the
treatment in Spain of the second Spanish patient with Ebola infection
repatriated to Spain.
Epidemiological update
Situation in West Africa
Since December 2013 and as of 5 October 2014, 8 032 cases of EVD, including 3
865 deaths, have been reported by WHO (Figure 1) [10].
The distribution of EVD cases by affected countries is as follows and is
presented in figure 1:
- Guinea: 1 298 cases and 768 deaths as of 5 October 2014;
- Liberia: 3 924 cases and 2 210 deaths as of 4 October 2014;
- Sierra Leone: 2 789 cases and 879 deaths as of 5 October 2014;
- Nigeria: 20 cases and 8 deaths, with last confirmed case in Lagos on 5 September 2014 (30 days as of 5 October 2014) and in Rivers State on first September 2014 (34 days as of 5 October);
- Senegal: 1 case, no deaths, confirmed on 28 August 2014 (38 days as of 5 October). All contacts have completed 21 days of follow-up.
Figure 1. Distribution of cases of EVD by week of reporting in
Guinea, Sierra Leone, Liberia, Nigeria and Senegal, weeks 48/2013 to 41/2014,
n=8 032*
*
The bar for week 41/2014 does not represent a complete week. The solid green
line represents the trends based on five week moving average plotted on the
fifth week of the moving average window. The figure includes one imported case
in Senegal.
The WHO Ebola response team showed that the current EVD cases present a
similar course of infection, signs and symptoms when compared to previous
outbreaks of EVD [9]. The incubation period was estimated to be 11.4 days with
serial interval of 15.3 days.
The case-fatality rate estimated among 4 010 cases with known clinical
outcome in Guinea, Liberia and Sierra Leone was 70.8% (95% CI: 68.6–72.8%) with
no noticeable difference between the countries.
Situation in Guinea, Sierra Leone and Liberia
Guinea, Liberia and Sierra Leone are experiencing widespread
intense transmission as per WHO categorisation [10]. The outbreak is still
evolving in these three countries (Figures 2 and 3). Officially reported figures
are believed to be underestimates [9]. The Guinean prefecture of Lola located in
the Nzérékoré Region and bordering Ivory Coast was added to the list of affected
areas on 2 October 2014 with 9 suspected cases reported, including 2 cases
confirmed by the Guinean Ministry of Health.
Figure 2. Distribution of cases of EVD by week of reporting in the three countries with widespread and intense transmission as of week 41 2014, n= 8 011*
*
The bar for week 41/2014 does not represent a complete calendar week. Source:
Data are based on official information reported by Ministries of Health up to
the end of 5 October for Guinea and Sierra Leone, and 4 October for Liberia.
[10]
Figure 3. Distribution of cases of EVD by week of reporting in Guinea, Sierra Leone, Liberia and Nigeria (as of week 40/2014)
Source:
Data from ministry of health reports (probable and confirmed cases).
Situation in Nigeria
As of 3 October 2014, 20 cases, including eight deaths have been notified.
The date of the last confirmed case in Lagos was on 5 September 2014 and in
Rivers State on 1 September 2014 [11]. All 891 identified contacts in Nigeria
have completed the 21-day follow-up (362 contacts in Lagos, 529 contacts in Port
Harcourt) [10].
Situation among healthcare workers in West Africa
As of 5 October 2014, WHO reported 401 healthcare workers infected with EVD
of which 232 died [10]. Table 2 details the distribution of cases and deaths
among healthcare workers in the four affected countries.
Table 1. Number of Ebola cases and deaths in healthcare workers
(HCW) in West Africa
| Country |
HCW cases
(% of reported cases)
|
HCW deaths
(% of reported deaths)
|
|---|---|---|
Guinea
|
73 (5.6)
|
38 (4.9)
|
Sierra Leone
|
129 (4.6)
|
95 (10.8)
|
Liberia
|
188 (4.8)
|
94 (4.3)
|
Nigeria
|
11 (55.0)
|
11 (55.0)
|
Total
|
401 (5.0)
|
232 (6.0)
|
Source: data are based on official information reported by Ministries
of Health as of 5 October for Guinea and Sierra Leone and 4 October for Liberia.
[10]
Situation outside of West Africa
United States of America
On 30 September 2014, the US CDC announced the first imported case of EVD
linked to the current outbreak in West Africa. The individual who had recently
arrived from Liberia was diagnosed in Dallas, Texas. This person is not a
healthcare worker and was visiting relatives in the USA. He is reported to have
had a high risk exposure in Liberia prior to travelling. He was reported to be
asymptomatic when leaving West Africa and remained asymptomatic while travelling
and upon arrival in the USA on 20 September. He developed symptoms around 24
September, sought medical care on 26 September and was hospitalised and isolated
on 28 September 2014. He died on 8 October 2014.
The US health authorities are investigating contact persons who may be at
risk of infection from this patient. This excludes people that were on the same
commercial airlines as the person was asymptomatic while travelling from Liberia
to the USA. The person reported developing symptoms only several days after the
flights and therefore was not contagious during that period.
As of 7 October 2014, the US CDC reports that the investigation of 10
contact persons with definite exposure to the case and 38 persons with possible
exposure is ongoing. It is reported for daily monitoring to be made with
contacts for up to 21 days after exposure to the case to check for fever and
other symptoms [12].
Spain
On 6 October, Spanish authorities reported a confirmed case of EVD in a
healthcare worker who participated in the medical care of the second Spanish
patient repatriated to Spain with Ebola infection. The medically evacuated
patient arrived in Spain on 22 September and died on 25 September. Yet, the
infected healthcare worker represents the first transmission of Ebola infection
outside of west Africa region Union [13].
The healthcare worker is a woman working in La Paz-Carlos III hospital in
Madrid. She reportedly developed fever the night of the 29 September. According
to the Spanish Ministry of Health, she participated in the medical care of the
repatriated patient and was wearing appropriate personal protection equipment.
She was admitted to La Paz-Carlos III Hospital on 6 October and is under strict
isolation [14].
The Spanish authorities have initiated contact tracing and, as of 9
October, 58 contacts of which five are considered as high-risk contacts, are
being monitored. Quarantine has been established or is under assessment for high
risk contacts.
Preliminary results of the investigation point to an incident during the
removal of the personal protection equipment (PPE) on 24 September as the mode
of transmission.
Medical evacuations from EVD-affected countries
Fourteen of Ebola virus infected individuals have been evacuated from the
EVD-affected countries (Table 2, Figure 4).
Table 2. Medical evacuation from EVD-affected countries up to 08
October 2014
Date of evacuation
(in 2014)
|
Evacuated from
|
Evacuated to
|
Profession
|
Status
|
Confirmed
|
Citizenship
|
|---|---|---|---|---|---|---|
| 02 August 2014 |
Liberia
|
Atlanta (USA)
|
Healthcare worker
|
Discharged
|
Yes
|
US
|
| 05 August 2014 |
Liberia
|
Atlanta (USA)
|
Healthcare worker
|
Discharged
|
Yes
|
US
|
| 06 August 2014 |
Liberia
|
Madrid (Spain)
|
Healthcare worker
|
Death
|
Yes
|
Spanish
|
| 24 August 2014 |
Sierra Leone
|
London (United Kingdom)
|
Healthcare worker
|
Stable
|
Yes
|
British
|
| 27 August 2014 |
Sierra Leone
|
Hamburg (Germany)
|
Epidemiologist
|
Recovered
|
Yes
|
Senegalese
|
| 04 September 2014 |
Monrovia, Liberia
|
Omaha, Nebraska (USA)
|
Physician (obstetrician)
|
stable
|
Yes
|
US
|
| 09 September 2014 |
Kenema, Sierra Leone
|
Atlanta, Georgia (USA)
|
Physician
|
stable
|
Yes
|
US
|
| 14 September 2014 |
Sierra Leone
|
Leiden (The Netherlands)
|
Healthcare worker
|
Discharged
|
No
|
Dutch
|
| 14 September 2014 |
Sierra Leone
|
Leiden (The Netherlands)
|
Healthcare worker
|
Discharged
|
No
|
Dutch
|
| 19 September 2014 |
Liberia
|
Paris (France)
|
Healthcare worker
|
Discharged
|
Yes
|
French
|
| 22 September 2014 |
Sierra Leone
|
Madrid (Spain)
|
Healthcare worker
|
Serious condition
upon evacuation
|
Yes
|
Spanish
|
| 22 September 2014 |
Sierra Leone
|
Lausanne (Switzerland)
|
Healthcare worker
|
Admitted
|
Unknown
|
Non-Swiss
|
| 28 September 2014 |
Sierra Leone
|
Maryland (USA)
|
Healthcare worker
|
Admitted
|
Unknown
|
US
|
| 02 October 2014 |
Sierra Leone
|
Frankfurt (Germany)
|
Healthcare worker
|
stable
|
Yes
|
Uganda
|
| 02 October 2014 |
Liberia
|
(USA)
|
Cameraman
|
Stable
|
Yes
|
US
|
| 06 October 2014 |
Sierra Leone
|
Oslo (Norway)
|
Healthcare worker
|
not known
|
Yes
|
Norway
|
| 08 October 2014 |
Liberia
|
Leipzig (Germany)
|
Laboratory worker
|
not known
|
Yes
|
Sudan
|
Figure 4. Medical evacuation from EVD-affected countries, as of 8
October 2014
EVD epicurve data
Cumulative number of cases and deaths for the five West African countries with reported EVD cases (Liberia, Guinea, Sierra Leone, Nigeria, Senegal). Source: WHO
Cumulative number of cases and deaths for the five West African countries with reported EVD cases (Liberia, Guinea, Sierra Leone, Nigeria, Senegal). Source: WHO
EVD map dataCumulative number
of cases and deaths at subnational level of the five West African countries with
reported EVD cases (Liberia, Guinea, Sierra Leone, Nigeria, Senegal). Source:
National situation report
For those weeks without reported data, the most recent figures were used as best estimate of the number of case).
For those weeks without reported data, the most recent figures were used as best estimate of the number of case).
References
1. World Health Organization. Ebola virus disease in Guinea [Internet].
Geneva: WHO; 2014 Mar 23 [cited 2014 Oct 8]. Available from: http://www.who.int/csr/don/2014_03_23_ebola/en/.
2. World Health Organization. Ebola virus disease - Fact sheet No103.
[Internet]. Geneva: WHO; 2014 [updated 2014 Sep; cited 2014 Oct 8]. Available
from: http://www.who.int/mediacentre/factsheets/fs103/en/.
3. Baize S, Pannetier D, Oestereich L, Rieger T, Koivogui L, al. e.
Emergence of Zaire Ebola Virus Disease in Guinea. N Engl J Med [Internet]. 2014
Apr 16. Available from: http://www.nejm.org/doi/full/10.1056/NEJMoa1404505.
4. Muyembe-Tamfum JJ, Mulangu S, Masumu J, Kayembe JM, Kemp A, Paweska JT.
Ebola virus outbreaks in Africa: past and present. Onderstepoort J Vet Res.
2012;79(2):451.
5. Centers for Disease Control and Prevention. Ebola in Liberia [Internet].
Atlanta: CDC; 2014 [cited 2014 Aug 26]. Available from: http://wwwnc.cdc.gov/travel/notices/alert/ebola-liberia.
6. Centers for Disease Control and Prevention. Ebola in Sierra Leone
[Internet]. Atlanta: CDC; 2014 [cited 2014 Sep 30]. Available from: http://wwwnc.cdc.gov/travel/notices/alert/ebola-sierra-leone.
7. World Health Organization. WHO statement on the meeting of the
International Health Regulations Emergency Committee regarding the 2014 Ebola
outbreak in West Africa [Internet]. Geneva: WHO; 2014 [cited 2014 Aug 29].
Available from: http://who.int/mediacentre/news/statements/2014/ebola-20140808/en/.
8. United Nations Security Council. Resolution 2177 (2014). Adopted by the
Security Council at its 7268th meeting on 18 September 2014 [Internet]: UN; 2014
[cited 2014 Oct 8]. Available from: http://www.ifrc.org/docs/IDRL/UN%20SC%20Res.pdf.
9. WHO Ebola Response Team. Ebola Virus Disease in West Africa — The First
9 Months of the Epidemic and Forward Projections. N Eng J Med [Internet]. 2014
Sep 23 [cited 2014 Sep 30]. Available from: http://www.nejm.org/doi/full/10.1056/NEJMoa1411100.
10. World Health Organization. Ebola response roadmap situation report. 8
October 2014. [Internet]. Geneva: WHO; 2014. Available from: http://apps.who.int/iris/bitstream/10665/136020/1/roadmapsitrep_8Oct2014_eng.pdf?ua=1.
11. World Health Organization. Ebola response roadmap situation report. 3
October 2014 [Internet]. Geneva: WHO; 2014. Available from: http://apps.who.int/iris/bitstream/10665/135765/1/roadmapupdate3oct14_eng.pdf?ua=1.
12. Centers for Disease Control and Prevention. First Imported Case of
Ebola Diagnosed in the United States [Internet]. Atlanta: CDC; 2014 [cited 2014
Oct 8]. Available from: http://www.cdc.gov/vhf/ebola/outbreaks/2014-west-africa/united-states-imported-case.html#ebola-contact-tracing.
13. Ministerio de Sanidad Servicios Sociales e Igualdad. Diagnosticado un
caso secundario de contagio por virus Ébola [press release in Spanish]
[Internet]. 2014 [cited 2014 Oct 6]. Available from: http://www.msssi.gob.es/gabinete/notasPrensa.do?id=3427.
14. Ministerio de Sanidad Servicios Sociales e Igualdad. Sanidad y la
Comunidad de Madrid constituyen una Comisión de coordinación para realizar el
seguimiento del virus Ébola [press release in Spanish] [Internet]. 2014 [cited
2014 Oct 7]. Available from: http://www.msssi.gob.es/gabinete/notasPrensa.do?id=3428.
Source: ECDC
Δεν υπάρχουν σχόλια:
Δημοσίευση σχολίου