Fig 1Table 1Table 2Table 3Table 4Reference 1Reference 2Reference 3Reference 4Reference 5Reference 6Reference 7Reference 8Reference 9Reference 10Reference 11Reference 12Reference 13Reference 14Reference 15Reference 16Reference 17Reference 18Reference 19Reference 20Reference 21Reference 22Reference 23Reference 24Reference 25Reference 26Reference 27Reference 28Reference 29Reference 30Insight ReviewThe 2014 Ebola virus disease outbreak in WestAfricaDerek GathererCorrespondenceDerek [email protected] of Biomedical & Life Sciences, Faculty of Health & Medicine, Lancaster University,Lancaster LA1 4YQ, UKOn 23 March 2014, the World Health Organization issued its first communique´on a newoutbreak 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 ofWest Africa, Guinea is the first country in this geographical region in which an outbreak of EVDhas occurred, leaving aside the single case reported in Ivory Coast in 1994. Cases have now alsobeen confirmed across Guinea as well as in the neighbouring Republic of Liberia. The appearanceof cases in the Guinean capital, Conakry, and the transit of another case through the Liberiancapital, 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 causativeagent has now been identified as an outlier strain of Zaire Ebola virus. The full geographical extentand degree of severity of the outbreak, its zoonotic origins and its possible spread to othercontinents are sure to be subjects of intensive discussion over the next months.IntroductionOn 23 March 2014, the World Health Organization(WHO) issued its first communique´(WHO, 2014a) on anew outbreak of Ebola virus disease (EVD), which began inDecember 2013 in the Republic of Guinea, initially in thePrefecture (province) of Gue´cke´dou in Guinea’s easternrainforest region, Guine´e Forestie`re (Forested Guinea), thenspreading to the Prefecture of Macenta, 80 km to the east.Located on the Atlantic coast of West Africa, Guinea is thefirst country in this geographical region to report an EVDoutbreak with more than one case (Fig. 1a). Cases havenow also been reported at several other locations inGuinea, as well as in neighbouring Liberia (Fig. 1b). Theappearance of cases in the Guinean capital, Conakry,represents the first large urban setting for EVD transmis-sion. Another case passed through the Liberian capital,Monrovia, but with no reports of any further transmissionwithin the city. Suspected cases in the neighbouri ngrepublics of Mali and Sierra Leone have so far testednegative at the time of writing (Fig. 1b, 25 April 2014).Clinical profileEVD is a severe haemo rrhagic fever caused by negative-sense ssRNA viruses classified by the International Com-mittee on Taxonomy of Viruses as belonging to the genusEbolavirus in the family Filoviridae (order Mononega-virales). Filovirus particles are 80 nm in diameter and formtwisted filaments (hence the name) of up to 1.1mminlength. One other genus in this family, Marburgvirus,contains viruses causing a similar disease to EVD. The thirdgenus, Cuevavirus, is confined to bat hosts. The case fatalityrate in EVD is so high, approaching 90 % in some outbreaks(Table 1), that members of the family Filoviridae have beenclassified as Category A potential bioterrorism agents by theCenters for Disease Control and Prevention (CDC, 2014).All bodily fluids are infectious, requiring the use of full-bodyprotective clothing by medical and surveillance staff.Epidemiological control is also made especially difficultdue to the highly variable incubation period of 1–25 days(Dowell et al., 1999), and the long Ebola virus-positiveperiod of some recovered patients (Rodriguez et al., 1999;Rowe et al., 1999). These figures are necessarily approximatebecause of the low number of confirmed survivors in whichtesting has been carried out. Patients initially present withfever, headache, joint/muscle and abdominal pain accom-panied by diarrhoea and vomiting (Paessler & Walker,2013). In its early stages, EVD is easily confused with othertropical fevers, such as malaria or dengue, until theappearance of the haemorrhagic terminal phase, presentingwith the characteristic internal and subcutaneous bleeding,vomiting of blood and reddening of the eyes. If sufficientblood is lost, this leads to renal failure, breathing difficulties,low body temperature, shock and death (Paessler & Walker,2013). ‘Cytokine storm’ with immune suppression of CD4and CD8 lymphocytes is a candidate mechanism forproduction of the terminal haemorrhagic fever (Wauquieret al., 2010). Current treatment of EVD is purelysymptomatic. However, the antiviral drug favipiravir hasproduced some promising results in laboratory-infectedJournal of General Virology (2014), 95, 1619–1624 DOI 10.1099/vir.0.067199-0067199G2014 The Authors Printed in Great Britain 1619MaliS. Sudan (335)GambiaSenegalGuinea-BissauKamsarConakry642173DinguirayeKourémaléSibiribougouBankoumanaMaliN’zérékoréBongFoya89FirestoneTapetaIvory CoastLiberiaIvoryCoastCongoCabonDRC*DabolaGuineaKissidougouMacentaKambiaGuéckédouKonoSierra leoneGrand Cape MountMonrovia(b)(d)LabéBoké5Congo (249)Gabon (209)Uganda (606)DRC (Zaire)(987)SLIC(1)(a)(c)25020015010050021 51464136Days after 1 March 2014 NumberCasesDeaths3126 56Fig. 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 areshown 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-confirmedoutbreak 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 toDabola (unknown); 5, transmission to Conakry (before 17 March 2014); 6, funeral of Conakry victim returns to Watagala (Dinguiraye Prefecture); 7, transmission
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