Epidemiological update: Outbreak of Ebola virus disease in West Africa , 23 November 2015

epidemiological update

​On 20 November 2015, the Liberian Ministry of Health and Social Welfare reported three confirmed cases of Ebola virus disease.

Background

An epidemic of Ebola virus disease (EVD) has been ongoing in West Africa since December 2013, mainly affecting Guinea, Liberia and Sierra Leone. On 8 August 2014, WHO declared the Ebola epidemic in West Africa a Public Health Emergency of International Concern (PHEIC). As of 18 November 2015, WHO has reported 28 598 cases of Ebola virus disease related to the outbreak in West Africa, including 11 299 deaths [1]. The number of cases in the most affected countries peaked in autumn 2014 and has been slowly decreasing since. Liberia was declared Ebola-free by WHO on 3 September 2015 and Sierra Leone on 7 November. Guinea has not reported new cases since 29 October 2015.  
 

Current situation in Liberia

On 20 November 2015, the Liberian Ministry of Health and Social Welfare reported three confirmed cases of Ebola virus disease [2]. On 19 November 2015, a reference laboratory in Liberia reported an Ebola positive result in a sample from a patient who presented symptoms such as fever, weakness and bleeding at a hospital in Monrovia on 17 November 2015. The patient was placed in isolation. The Liberian Ministry of Health and Social Welfare stated in a press release that four patients and high risk contacts are cared for at an Ebola Treatment Unit in Monrovia. The hospital where the patient was detected is undergoing decontamination and all health care workers who were in contact with the patient are being monitored. 
 
According to media, the first case is a boy with onset of symptoms on 14 November [3,4], who attended school on Monday 16 November, was admitted to a hospital on 17 November and  confirmed positive on two samples on the 19 November 2015. Two additional cases have been identified among family members.  As of 20 November 2015, four patients (corresponding to at least three confirmed cases) and high risk contacts are hospitalised in an Ebola Treatment Unit in Monrovia. According to media, 153 contacts presenting with high, medium and low-risk exposure are followed-up [5]. Further response activities and contact tracing are on-going.
 

Assessment 

Liberia was declared free of Ebola virus transmission in the human population on 3 September 2015. Following which, Liberia entered a 90-day period of EVD heightened surveillance [6]. The confirmation of new EVD cases during heightened surveillance periods after the tail end of outbreaks is not unexpected as stated in the most recent ECDC risk assessments [7,8]. 
 
The identification of new cases in Liberia highlights the importance of maintaining enhanced surveillance and immediate response capacity for control in the aftermath of the Ebola epidemic in the affected countries.

Rapid risk assessment: Outbreak of Ebola virus disease in West Africa. 13th update, 13 October 2015. [Internet]. Stockholm: ECDC; 2015

References

  1. World Health Organization. Ebola Situation Report - 18 November 2015 Geneva: world Health Organization,; 2015 [cited 2015 23 November 2015].
  2. Ministry of Health & Social Welfare Republic of Liberia. Press statement, November 20, 2015 2015 [cited 2015 23 November 2015].
  3. MacDougall C, Cooper H. Ebola Cases in 3 Family Members Confirmed in Liberia. The New York Times. 2015 20 November 2015.
  4. Centre for Infectious Disease Research and Policy. Family case cluster ends Liberia's Ebola-free status 2015.
  5. Reuters. Liberia monitors over 150 Ebola contacts as virus re-emerges. Reuteres. 2015.
  6. World Health Organization. Criteria for declaring the end of the Ebola outbreak in Guinea, Liberia or Sierra Leone Geneva: World Health Organization; 2015.
  7. European Centre for Disease Prevention and Control. Rapid risk assessment: Outbreak of Ebola virus disease in West Africa. 12th update, 1 July 2015. [Internet]. Stockholm: ECDC; 2015
  8. European Centre for Disease Prevention and Control. Rapid risk assessment: Outbreak of Ebola virus disease in West Africa. 13th update, 13 October 2015. [Internet]. Stockholm: ECDC; 2015.