Epidemiological update: Outbreak of Ebola virus disease in West Africa, 2 October 2014

epidemiological update

​Since December 2013 and as of 28 September 2014, WHO reports 7 178 cases of Ebola virus disease (EVD) including 3 338 deaths.

 This is the first outbreak of EVD in West Africa and it is unprecedented in size and geographical distribution, affecting densely populated urban areas. WHO reported 915 new cases and 421 deaths since the previous ECDC update of 26 September 2014.

The distribution of cases and fatalities by countries is as follows:

Cases and deaths of EVD, West Africa affected countries, as of 28 September 2014, week 40

Country Cases Deaths
Guinea 1 157 710
Sierra Leone 2 304 622
Liberia 3 696 1 998
Nigeria 20 8
Total 7 177 3 338

Note: one imported case has been reported from Senegal
 
WHO reported that 377 of the cases occurred in healthcare workers, including 216 deaths.
Despite the apparent decrease in the overall number of new cases, it is acknowledged by WHO that “EVD cases are under-reported from several key locations. Transmission remains persistent and widespread in Guinea, Liberia and Sierra Leone, with strong evidence of increasing case incidence in several districts. There are few signs yet that the EVD epidemic in West Africa is being brought under control.”
 
To date, two cases apart those cases that have been medically-evacuated from West Africa, have been found to be positive outside Guinea, Liberia, Nigeria or Sierra Leone:

  • one imported case in Senegal (a Guinean citizen who arrived from Guinea) and reported previously. In Senegal, there were no further cases of Ebola reported, none of the contacts of the infected person experienced symptoms of Ebola during the 21-day incubation period.
  • On 30 September 2014, the US Centers for Disease Prevention and Control (CDC) announced the first imported case of Ebola 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. The person arrived in the USA on 20 September and developed symptoms around 24 September, then sought medical care on 26 September and was hospitalised and isolated on 28 September 2014. The US health authorities are investigating contact persons in the USA who may be at risk of infection from this patient. It is very unlikely that the individual would have infected others during the flights as the person did not exhibit symptoms of Ebola during the flights and Ebola is only contagious if the person is experiencing active symptoms.

Distribution of reported cases of EVD by week in Guinea, Sierra Leone, Liberia, and Nigeria, week 48/2013 to 40/2014 (data as of 28 September 2014*)

Source: adapted from WHO*The bar for week 40/2014 does not represent a complete week.

Distribution of confirmed, probable and suspected EVD cases by district and week of reporting, weeks 33-39, 2014

*Source: adapted from national situation reports, when available.

Distribution of cases of Ebola virus disease by week of reporting in Guinea, Liberia, and Sierra Leone, as of 28 September 2014, week 40/2014

Source: Adapted from WHO, data for week 40 are incomplete