Journal of General Virology 2014 95 1619 1624 Insight Review DOI 10 1099 vir 0 067199 0 The 2014 Ebola virus disease outbreak in West Africa Derek Gatherer Correspondence Derek Gatherer Division of Biomedical Life Sciences Faculty of Health Medicine Lancaster University Lancaster LA1 4YQ UK d gatherer lancaster ac uk On 23 March 2014 the World Health Organization issued its first communique on a new outbreak of Ebola virus disease EVD which began in December 2013 in Guine e Forestie re Forested Guinea the eastern sector of the Republic of Guinea Located on the Atlantic coast of West Africa Guinea is the first country in this geographical region in which an outbreak of EVD has occurred leaving aside the single case reported in Ivory Coast in 1994 Cases have now also been confirmed across Guinea as well as in the neighbouring Republic of Liberia The appearance of cases in the Guinean capital Conakry and the transit of another case through the Liberian capital Monrovia presents the first large urban setting for EVD transmission By 20 April 2014 242 suspected cases had resulted in a total of 147 deaths in Guinea and Liberia The causative agent has now been identified as an outlier strain of Zaire Ebola virus The full geographical extent and degree of severity of the outbreak its zoonotic origins and its possible spread to other continents are sure to be subjects of intensive discussion over the next months Introduction On 23 March 2014 the World Health Organization WHO issued its first communique WHO 2014a on a new outbreak of Ebola virus disease EVD which began in December 2013 in the Republic of Guinea initially in the Prefecture province of Gue cke dou in Guinea s eastern rainforest region Guine e Forestie re Forested Guinea then spreading to the Prefecture of Macenta 80 km to the east Located on the Atlantic coast of West Africa Guinea is the first country in this geographical region to report an EVD outbreak with more than one case Fig 1a Cases have now also been reported at several other locations in Guinea as well as in neighbouring Liberia Fig 1b The appearance of cases in the Guinean capital Conakry represents the first large urban setting for EVD transmission Another case passed through the Liberian capital Monrovia but with no reports of any further transmission within the city Suspected cases in the neighbouring republics of Mali and Sierra Leone have so far tested negative at the time of writing Fig 1b 25 April 2014 Clinical profile EVD is a severe haemorrhagic fever caused by negativesense ssRNA viruses classified by the International Committee on Taxonomy of Viruses as belonging to the genus Ebolavirus in the family Filoviridae order Mononegavirales Filovirus particles are 80 nm in diameter and form twisted filaments hence the name of up to 1 1 mm in length One other genus in this family Marburgvirus 067199 G 2014 The Authors Printed in Great Britain contains viruses causing a similar disease to EVD The third genus Cuevavirus is confined to bat hosts The case fatality rate in EVD is so high approaching 90 in some outbreaks Table 1 that members of the family Filoviridae have been classified as Category A potential bioterrorism agents by the Centers for Disease Control and Prevention CDC 2014 All bodily fluids are infectious requiring the use of full body protective clothing by medical and surveillance staff Epidemiological control is also made especially difficult due to the highly variable incubation period of 1 25 days Dowell et al 1999 and the long Ebola virus positive period of some recovered patients Rodriguez et al 1999 Rowe et al 1999 These figures are necessarily approximate because of the low number of confirmed survivors in which testing has been carried out Patients initially present with fever headache joint muscle and abdominal pain accompanied by diarrhoea and vomiting Paessler Walker 2013 In its early stages EVD is easily confused with other tropical fevers such as malaria or dengue until the appearance of the haemorrhagic terminal phase presenting with the characteristic internal and subcutaneous bleeding vomiting of blood and reddening of the eyes If sufficient blood is lost this leads to renal failure breathing difficulties low body temperature shock and death Paessler Walker 2013 Cytokine storm with immune suppression of CD4 and CD8 lymphocytes is a candidate mechanism for production of the terminal haemorrhagic fever Wauquier et al 2010 Current treatment of EVD is purely symptomatic However the antiviral drug favipiravir has produced some promising results in laboratory infected 1619 b Gambia Sibiribougou Senegal Kour mal Guinea Bissau Bok Mali Kamsar IC 1 SL S Sudan 335 Congo 249 Gabon 209 Lab 6 Bankoumana Mali Dinguiraye Dabola Guinea 5 4 Conakry Kambia Kissidougou 2 Macenta 1 Gu ck dou 7 3 Kono N z r kor Foya Sierra leone 8 Bong Ivory Coast Grand Cape Mount Firestone Uganda 606 DRC Zaire 987 Monrovia c 9 Tapeta Liberia d 250 200 Number 150 Ivory Coast 100 Congo 50 Cabon Cases Deaths DRC 0 21 26 31 36 41 46 51 Days after 1 March 2014 56 Journal of General Virology 95 Fig 1 a Guinea red and Liberia yellow where cases in the current EVD outbreak have been confirmed Countries with candidate cases that have tested negative are shown in green and countries with previous EVD outbreaks in blue with the total numbers of cases in previous outbreaks from 1976 to 2012 shown in parentheses DRC Democratic Republic of Congo IC Ivory Coast SL Sierra Leone b Spread of EBOV within Guinea and neighbouring countries Red circles indicate WHO confirmed outbreak areas and black circles indicate areas where candidate cases have proved negative 1 Initial cases in Gue cke dou from December 2013 transmitted to Macenta February 2014 2 transmission to Macenta to Kissidougou late February 2014 3 transmission from Macenta to N ze re kore February March 2014 4 transmission to Dabola unknown 5 transmission to Conakry before 17 March 2014 6 funeral of Conakry victim returns to Watagala Dinguiraye Prefecture 7 transmission from Gue cke dou to Liberia March 2014 8 Liberian case travels from Foya Lofa county to Monrovia Montserrado County 29 March 2014 9 case travels on to Firestone Margibi County dies 2 April 2014 c WHO cumulative incidence of candidate cases of EBOV in Guinea only Liberia not included through late March and early April 2014 d Fruit bat ranges little collared fruit bat green and hammer headed fruit bat red The asterisk indicates Gue cke dou outbreak initial
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