Daniel Mukadi-Bamuleka, Emerencienne Kibangou, Vital Mondonge Makuma, Ibrahima Socé Fall, Etienne Yuma, Guylain Kabongo, Oliver Morgan, Franck Mboussou, Katy A. M. Gaythorpe, Pierre Nouvellet, Boubacar Diallo, Anne Cori, Guillaume Ngoy, Ousmane Ly, Zabulon Yoti, Augustin Mamba, Roland Ngom, Yokouide Allarangar, Benido Impouma, Neil M. Ferguson, Patricia Ndumbi Ngamala, Richard G. FitzJohn, Jean de Dieu Lukwesa Mwati, Yahaya Ali Ahmed, Maria D. Van Kerkhove, Oly Ilunga Kalenga, Aaron Aruna Abedi, Pierre Formenty, Oscar Mavila, Théophile Bokenge, Natsuko Imai, Alpha Forna, Ahmadou Barry, Yyonne Lay, Tini Garske, Tamayi Mlanda, Anny Mutombo, Anne Fortin, Annika Wendland, Theresa M. Lee, Charles Okot Lukoya, Rodney Towner, Amadou Mouctar Diallo, Ernest Dabire, Sheila Makiala-Mandanda, Michael J. Ryan, Christopher Haskew, Steve Ahuka-Mundeke, Guy Kalambayi Kabamba, Julienne Anoko, Tshewang Choden Dorji, Jean Jaques Muyembe, Emma Kitenge, Celine Gurry, Gaston Tshapenda, Gisele Mbuy, Mamoudou Harouna Djingarey, Emanuele Bruni, Marie Roseline Darnycka Belizaire, Aura Rocio Escobar Corado Waeber, N'Da Konan Michel Yao, Justus Nsio, Patrick Mukadi Kakoni, Reinhilde Van De Weerdt, Esther L Hamblion, Kevin Babila Ousman, Ndjoloko Tambwe Bathé, Sangeeta N. Bhatia, Brett Nicholas Archer, Alhassane Touré, Jayshree Bagaria, Christl A. Donnelly, Placide Mbala-Kingebeni, Emilie Peron, Ilaria Dorigatti, Gervais Leon Folefack Tengomo, Leopold Lubula, Stéphane Hugonnet, Jonathan A. Polonsky, Anastasie Mujinga Mulumba, Medical Research Council (MRC), Bill & Melinda Gates Foundation, National Institute for Health Research, National Institutes of Health, and USAID
Background\ud \ud On May 8, 2018, the Government of the Democratic Republic of the Congo reported an outbreak of Ebola virus disease in Équateur Province in the northwest of the country. The remoteness of most affected communities and the involvement of an urban centre connected to the capital city and neighbouring countries makes this outbreak the most complex and high risk ever experienced by the Democratic Republic of the Congo. We provide early epidemiological information arising from the ongoing investigation of this outbreak.\ud Methods\ud \ud We classified cases as suspected, probable, or confirmed using national case definitions of the Democratic Republic of the Congo Ministère de la Santé Publique. We investigated all cases to obtain demographic characteristics, determine possible exposures, describe signs and symptoms, and identify contacts to be followed up for 21 days. We also estimated the reproduction number and projected number of cases for the 4-week period from May 25, to June 21, 2018.\ud Findings\ud \ud As of May 30, 2018, 50 cases (37 confirmed, 13 probable) of Zaire ebolavirus were reported in the Democratic Republic of the Congo. 21 (42%) were reported in Bikoro, 25 (50%) in Iboko, and four (8%) in Wangata health zones. Wangata is part of Mbandaka, the urban capital of Équateur Province, which is connected to major national and international transport routes. By May 30, 2018, 25 deaths from Ebola virus disease had been reported, with a case fatality ratio of 56% (95% CI 39–72) after adjustment for censoring. This case fatality ratio is consistent with estimates for the 2014–16 west African Ebola virus disease epidemic (p=0·427). The median age of people with confirmed or probable infection was 40 years (range 8–80) and 30 (60%) were male. The most commonly reported signs and symptoms in people with confirmed or probable Ebola virus disease were fever (40 [95%] of 42 cases), intense general fatigue (37 [90%] of 41 cases), and loss of appetite (37 [90%] of 41 cases). Gastrointestinal symptoms were frequently reported, and 14 (33%) of 43 people reported haemorrhagic signs. Time from illness onset and hospitalisation to sample testing decreased over time. By May 30, 2018, 1458 contacts had been identified, of which 746 (51%) remained under active follow-up. The estimated reproduction number was 1·03 (95% credible interval 0·83–1·37) and the cumulative case incidence for the outbreak by June 21, 2018, is projected to be 78 confirmed cases (37–281), assuming heterogeneous transmissibility.\ud Interpretation\ud \ud The ongoing Ebola virus outbreak in the Democratic Republic of the Congo has similar epidemiological features to previous Ebola virus disease outbreaks. Early detection, rapid patient isolation, contact tracing, and the ongoing vaccination programme should sufficiently control the outbreak. The forecast of the number of cases does not exceed the current capacity to respond if the epidemiological situation does not change. The information presented, although preliminary, has been essential in guiding the ongoing investigation and response to this outbreak.