Epidemiological update: Outbreak of Ebola virus disease in West Africa, 15 January 2015
Since the last epidemiological update on Ebola virus disease (EVD) published on 9 January 2015, and as of 12 January 2015, WHO has reported 357 additional cases in the affected countries and 185 additional deaths.
Since the last epidemiological update on Ebola virus disease (EVD) published on 9 January 2015, and as of 12 January 2015, WHO has reported 357 additional cases in the affected countries and 185 additional deaths. As of 12 January 2015, WHO has reported 21 427 confirmed, probable, and suspected cases of Ebola virus disease (EVD), with 8 459 deaths, in four affected countries (Guinea, Liberia, Mali and Sierra Leone) and four previously affected countries (Nigeria, Senegal, Spain and the United States of America).
According to WHO, in week two of 2015 Guinea reported its lowest weekly number of new confirmed EVD cases since mid-August 2014. Case numbers remain low in Liberia, showing the lowest weekly number of confirmed cases since the first week of June 2014. Sierra Leone has now reported a decline in case incidence for the second week running, and recorded its lowest weekly number of new confirmed cases since the end of August 2014.
On 29 December 2014, Scotland reported the first imported case of EVD to the UK that was not a medical evacuation. According to WHO, all possible contacts of the case have been investigated and no high risk contacts have been identified.
According to WHO, Mali will be declared Ebola free on 18 January 2015.
Distribution of cases
Countries with widespread and intense transmission:
- Guinea: 2 817 cases and 1 821 deaths (as of 12 January 2015)
- Liberia: 8 362 cases and 3 556 deaths (as of 12 January 2015)
- Sierra Leone: 10 150 cases and 3 067 deaths (as of 12 January 2015)
Countries with an initial case or cases, or with localised transmission:
- United Kingdom: one confirmed case on 29 December 2014
- United States: four cases including one death. The last case tested negative on 11 November 2014 in New York.
- Mali: eight cases, six deaths. According to WHO, Mali will be declared Ebola free on 18 January 2015
- Nigeria, Senegal and Spain have been declared free of EVD after having cases related to the current epidemic in West Africa
Figure 1 . Distribution of cases of EVD by week of reporting in Guinea, Sierra Leone, Liberia, Nigeria, Senegal and Mali, weeks 48/2013 to 03/2015, as of 12 January 2015
* In week 45/2014, the WHO carried-out a retrospective correction in the data resulting in reporting 299 fewer cases resulting in a negative value for new cases in week 45 which is not plotted. . ** According to the WHO the marked increase in the cumulative total number of cases in week 43 is due to a more comprehensive assessment of patient databases leading to 3 792 additional reported cases. However, these cases have occurred throughout the epidemic period.
The green line represents the trend based on a five week moving average plotted on the fifth week of the moving average window. The figure includes cases in Nigeria (20), Senegal (1) and Mali (4). (See WHO Ebola response roadmap: Situation report, 26 November 2014)
Situation in the affected West African countries
Quoting the latest WHO Ebola Situation Report, each of the intense-transmission countries has sufficient capacity to isolate and treat patients, with more than two treatment beds per reported confirmed and probable case. However, the uneven geographical distribution of beds and cases, and the under-reporting of cases, means that not all EVD cases are isolated in several areas.
Between 84 and 99% of registered contacts are being monitored in the three countries with intense transmission, though the number of contacts traced per EVD case remains lower than expected in many districts.
The cumulative case-fatality rate in the three intense-transmission countries among hospitalized patients is between 57 and 60%.
According to WHO, Mali will be declared Ebola-free on 18 January 2015. The last confirmed case in Mali tested negative for the second time on 6 December 2014. All identified contacts connected with both the initial case in Kayes and the outbreak in Bamako have completed the 21-day follow-up period.
Figure 2. Distribution of cases of EVD by week of reporting, Guinea, Liberia and Sierra Leone, as of week 03/2015
* The marked increase in the number of cases reported in Sierra Leone (week 44) and Liberia (week 43) results from a more comprehensive assessment of patient databases. The additional 3 792 cases have occurred throughout the epidemic period.Source: Data are based on official information reported by ministries of health up to the end of 2 November for Guinea and Sierra Leone and 31 October for Liberia. (See WHO Ebola response roadmap: Situation report, 5 November 2014)
** In week 45/2014, WHO reported 476 fewer cases than the week before in Sierra Leone due to retrospective corrections. § In week 44/2014, WHO reported zero cases for Liberia.
Figure 3. Distribution of cases of EVD by week of reporting in Guinea, Sierra Leone, Liberia and Mali (as of week 02/2015).
Source: Data from ministries of health reports (suspected, probable and confirmed cases).
Situation among healthcare workers
Up to the end of 11 January 2015, 843 healthcare workers (HCWs) are known to have been infected with EVD, 500 of whom have died. Distribution of cases: 159 HCWs in Guinea, 370 HCWs in Liberia, 296 HCWs in Sierra Leone, two HCWs in Mali, 11 HCWs infected in Nigeria, one HCW infected in Spain while treating an EVD-positive patient, one HCW in the UK who became infected in Sierra Leone, and three HCWs in the USA (one HCW infected in Guinea, and two HCWs infected during the care of a patient in Texas).
Table 1. Number of Ebola cases and deaths among healthcare workers, as of 11 January 2014.
|Country||Healthcare worker cases (% of reported cases)||Healthcare worker deaths (% of reported deaths)|
|Guinea||159 (5.7)||94 (5.2)|
|Liberia||370 (4.4)||178 (5.0)|
|Mali||2 (25.0)||2 (33.3)|
|Nigeria||11 (55.0)||5 (62.5)|
|Sierra Leone||296 (2.9)||221 (7.2)|
|United States||3 (75.0)||0|
|Total||834 (3.9)||500 (5.9)|
Source: Data are based on official information reported by Ministries of Health. (See WHO Ebola Situation report, 14 January 2015)
Situation outside West Africa
One case was reported in Scotland in a patient who travelled from Sierra Leone via Casablanca and London and arrived in Glasgow late on 28 December 2014.
Public Health England (PHE) has completed contact tracing following the confirmed case of Ebola in a healthcare worker returning from Sierra Leone. People contacted by Public Health England were made aware that a person on their flight was confirmed with Ebola after they returned to the UK, although the person would have been in the very early stages of disease and extremely unlikely to be infectious. The people sitting directly in the vicinity of the passenger (two rows adjacent, ahead and behind) were advised to take their temperature twice daily until 18 January 2015. If their temperature is 37.5°C or higher, or they begin to feel unwell in any way, they are advised to call a dedicated Public Health England contact immediately for advice.
No high-risk contacts have been identified in connection with the EVD case in the United Kingdom.
This is the largest ever documented epidemic of EVD in terms of numbers and geographical spread. The evolving epidemic of EVD increases the likelihood that EU residents and travellers to the EVD-affected countries will be exposed to infected or ill persons. The risk of infection for residents and visitors in the affected countries through exposure in the community is considered low if they adhere to the recommended precautions. Residents and visitors to the affected areas run a risk of exposure to EVD in healthcare facilities. The level of this risk is related to how well the infection control measures are being implemented in these settings and the nature of the care required. As the epidemic is still evolving and international staff are deployed to the affected countries to support the epidemic control, there remains a risk of importation of EVD cases to the EU. The risk of Ebola virus spreading from an EVD patient who arrives in the EU as result of a planned medical evacuation is considered to be low when appropriate measures are strictly adhered to, but cannot be excluded in exceptional circumstances. If a symptomatic case of EVD presents in an EU Member State, secondary transmission to caregivers in the family and in healthcare facilities cannot be excluded. The highest risk is at an early stage of the disease, before the risk of EVD has been recognised and at the late stage of the disease when patients have very high viral loads and undergo invasive therapeutic procedures.
Download the data:
• Epi-curve data
Cumulative number of cases and deaths for the West African countries with reported EVD cases. Source: WHO
• Map data
Cumulative number of cases and deaths at subnational level in the West African countries with reported EVD cases. Source: National situation report.
For those weeks without reported data, the most recent figures were used as best estimate of the number of case.
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