[Source: PLoS Neglected Tropical Diseases, full page: (LINK). Abstract, edited.]
OPEN ACCESS / PEER-REVIEWED / RESEARCH ARTICLE
Urban yellow fever outbreak—Democratic Republic of the Congo, 2016: Towards more rapid case detection
Brecht Ingelbeen , Nadine A. Weregemere, Harold Noel, Gaston P. Tshapenda, Mathias Mossoko, Justus Nsio, Axelle Ronsse, Steve Ahuka-Mundeke, Sandra Cohuet, Benoît I. Kebela
Published: December 7, 2018 / DOI: https://doi.org/10.1371/journal.pntd.0007029 / This is an uncorrected proof.
Between December 2015 and July 2016, a yellow fever (YF) outbreak affected urban areas of Angola and the Democratic Republic of the Congo (DRC). We described the outbreak in DRC and assessed the accuracy of the YF case definition, to facilitate early diagnosis of cases in future urban outbreaks.
In DRC, suspected YF infection was defined as jaundice within 2 weeks after acute fever onset and was confirmed by either IgM serology or PCR for YF viral RNA. We used case investigation and hospital admission forms. Comparing clinical signs between confirmed and discarded suspected YF cases, we calculated the predictive values of each sign for confirmed YF and the diagnostic accuracy of several suspected YF case definitions. Fifty seven of 78 (73%) confirmed cases had travelled from Angola: 88% (50/57) men; median age 31 years (IQR 25–37). 15 (19%) confirmed cases were infected locally in urban settings in DRC. Median time from symptom onset to healthcare consultation was 7 days (IQR 6–9), to appearance of jaundice 8 days (IQR 7–11), to sample collection 9 days (IQR 7–14), and to hospitalization 17 days (IQR 11–26). A case definition including fever or jaundice, combined with myalgia or a negative malaria test, yielded an improved sensitivity (100%) and specificity (57%).
As jaundice appeared late, the majority of cases were diagnosed too late for supportive care and prompt vector control. In areas with known local YF transmission, a suspected case definition without jaundice as essential criterion could facilitate earlier YF diagnosis, care and control.
Yellow fever is a mosquito-borne viral infection characterized by fever, followed after several days by jaundice, liver or kidney failure, shock or bleeding in up to 25% of cases. Although the virus primarily circulates in forests among primates, it can also be transmitted from human to human by mosquitoes in urban areas. If infected patients are detected early, they could benefit from timely supportive treatment, and control measures such as mosquito bite prevention, mosquito control, and mass vaccination campaigns, could prevent further spread of the disease. During 2015–16 a yellow fever outbreak spread in urban areas of Angola and DRC. The present study showed that most yellow fever patients that were diagnosed in DRC had travelled from Angola where they have been infected, and that most were adult men. Nevertheless, several patients have been infected locally, in urban settings in three provinces of DRC. Patients were diagnosed only when jaundice appeared, more than a week after their illness started, too late to fully benefit from supportive treatment. During urban outbreaks, improving early access to healthcare and earlier detection of patients by recognizing acute fever when malaria infection is excluded, could improve yellow fever care and control.
Citation: Ingelbeen B, Weregemere NA, Noel H, Tshapenda GP, Mossoko M, Nsio J, et al. (2018) Urban yellow fever outbreak—Democratic Republic of the Congo, 2016: Towards more rapid case detection. PLoS Negl Trop Dis 12(12): e0007029. https://doi.org/10.1371/journal.pntd.0007029
Editor: David W.C. Beasley, University of Texas Medical Branch, UNITED STATES
Received: September 27, 2018; Accepted: November 27, 2018; Published: December 7, 2018
Copyright: © 2018 Ingelbeen et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: Anonymized data of suspected and confirmed yellow fever cases reported during the outbreak and for which symptoms were recorded (as of 11/08/2016) is available from the Open Science Framework database (url: osf.io/xkafm). Diagnostic and outcome data may have been updated after 11/08/2016.
Funding: The authors received no specific funding for this work.
Competing interests: The authors have declared that no competing interests exist.
Keywords: Yellow Fever; DRC.