Epidemiology and surveillance
The total number of probable and confirmed cases in the current outbreak of Ebola virus disease (EVD) in the four affected countries as reported by the respective Ministries of Health of Guinea, Liberia, Nigeria, and Sierra Leone is 3 069, with 1552 deaths.
The outbreak continues to accelerate. More than 40% of the total number of cases have occurred within the past 21 days. However, most cases are concentrated in only a few localities.
The overall case fatality rate is 52%. It ranges from 42% in Sierra Leone to 66% in Guinea.
A separate outbreak of Ebola virus disease, which is not related to the outbreak in West Africa, was reported on 24 August by the Democratic Republic of Congo (DRC) and is detailed in a separate edition of the Disease Outbreak News (http://who.int/csr/don/2014_08_27_ebola/en/)
Health sector response
A full understanding of the outbreak that will lead to improved response requires detailed analysis of exactly where transmission is occurring (by district level) and of time trends. This analysis is ongoing. Preliminary results show that cases are still concentrated (62% of all reported cases since the beginning of the outbreak) in the epicentre of the outbreak in Gueckedou (Guinea); Lofa (Liberia), where cases continue to rise; and Kenema and Kailahun (Sierra Leone). Capital cities are of particular concern, owing to their population density and repercussions for travel and trade.
WHO and its partners are on the ground establishing Ebola treatment centres and strengthening capacity for laboratory testing, contact tracing, social mobilization, safe burials, and non-Ebola health care.
WHO continues to monitor for reports of rumoured or suspected cases from countries around the world and systematic verification of these cases is ongoing. Countries are encouraged to continue engaging in active surveillance and preparedness activities. Cases of EVD have been reported from the Democratic Republic of Congo. The cases in DRC are not related to the outbreak in West Africa. Outside of the four affected countries in West Africa and DRC, no new cases have been confirmed in other countries.
WHO does not recommend any travel or trade restrictions be applied except in cases where individuals have been confirmed or are suspected of being infected with EVD or where individuals have had contact with cases of EVD. (Contacts do not include properly-protected health-care workers and laboratory staff.) Temporary recommendations from the Emergency Committee with regard to actions to be taken by countries can be found at http://who.int/mediacentre/news/statements/2014/ebola-20140808/en/.
As of 26 August 2014, the cumulative number of cases attributed to EVD in the four countries stands at 3 069, including 1 552 deaths. The distribution and classification of the cases are as follows: Guinea, 647 cases (482 confirmed, 141 probable, and 25 suspected), including 430 deaths; Liberia, 1 378 cases (322 confirmed, 674 probable, and 382 suspected), including 694 deaths; Nigeria, 17 cases (13 confirmed, 1 probable, and 3 suspected), including 6 deaths; and Sierra Leone, 1 026 cases (935 confirmed, 37 probable, and 54 suspected), including 422 deaths.
The total number of cases is subject to change due to ongoing reclassification, retrospective investigation, and availability of laboratory results. Data reported in the Disease Outbreak News are based on official information reported by Ministries of Health.