Epidemiological Update: Outbreak of Ebola Virus Disease in West Africa, 24 April 2014

Epidemiological update

​An outbreak of Ebola Virus Disease (EVD) with onset in December 2013 continues to evolve in the two West African countries of Guinea and Liberia. The first cases were reported from Guéckédou prefecture, a forested region of south-eastern Guinea near the border with Liberia and Sierra Leone. The alert was sent to the Ministry of Health on 10 March 2014. This is the first such outbreak in this region.

​Background
An outbreak of Ebola Virus Disease (EVD) with onset in December 2013 continues to evolve in the two West African countries of Guinea and Liberia. The first cases were reported from Guéckédou prefecture, a forested region of south-eastern Guinea near the border with Liberia and Sierra Leone. The alert was sent to the Ministry of Health on 10 March 2014. This is the first such outbreak in this region.
 
Update as of 24 April 2014

(source: WHO Global Alert and Response)

Guinea: As of 24 April, the Ministry of Health has reported 208 EVD cases, including 136 deaths (case fatality ratio 65%) comprised of 112 laboratory confirmed cases (69 deaths), 41 probable cases (34 deaths) and 55 suspected case (33 deaths). Six areas are affected, the capital Conakry (53 cases, 23 deaths) and five prefectures: Guéckédou (122 cases, 87 deaths), Macenta (22 cases, 16 deaths), Kissidougou (6 cases, 5 deaths), Dabola (4 cases, 4 deaths) and Djingaraye (1 case, 1 death). Since 17 April 2014, five new cases and seven deaths have been were reported from Conakry and Guéckédou, including 3 confirmed cases.
 
Liberia: As of 24 April, the Ministry of Health and Social Welfare has reported 34 EVD cases including 11 deaths since 13 March 2014. Of the reported cases, six are laboratory confirmed cases (6 deaths), two probable cases and 26 suspected cases. The six confirmed cases were reported from two counties: Lofa (4) and Margibi (2). The most recent confirmed case had a date of onset on 6 April and was admitted to hospital on 10 April. Seven new clinically compatible suspected cases and no deaths have been reported since 17 April 2014.

Other countries: All suspected EVD cases reported in Mali (6 cases) and in Sierra Leone (19 cases) were tested negative for ebolavirus and have been discarded.
 
No cases have been detected in returning travellers in Europe.
 
Conclusions
 
The outbreak is still evolving and it is expected that new cases will be reported from Guinea and Liberia in the coming weeks, and possibly from bordering countries. Isolation of cases, active monitoring of contacts and other control measures currently being implemented in the affected countries with the support of international partners, including a team of EU scientists and an EU funded mobile laboratory in Guéckédou, are expected to control this outbreak and prevent further spread of the disease.
The risk of infection for travellers visiting Guinea and Liberia is considered very low. Most human infections result from direct contact with bodily fluids or secretions from an infected human, and the highest risks of infection are associated with caring for infected patients, particularly in hospital settings, unprotected exposure to contaminated bodily fluids, and unsafe medical procedures, including exposure to contaminated medical devices, such as needles and syringes.
 
The origin of this outbreak remains unknown but phylogenetic analysis of the virus shows that the Guinean EBOV strain is a separate clade from the known ebolavirus strains circulating in Republic Democratic of Congo and Gabon.
 

Distribution of suspected and confirmed cases of EVD by week, Guinea, week 48/2013 to 17/2014