New strain of Ebola found in the Congo

18 November 2014

An outbreak of haemorrhagic fever in the Democratic Republic of the Congo (DRC) in August has been verified as Ebola but a different strain from that in the more well known outbreaks in west African countries, according to an international study. It was traced to a woman who cut up a dead monkey she found in the local forest.

The study by the Institut de Recherche pour le Développement(IRD), the Institut Pasteur, the CNRS, the CIRMF in Gabon, the INRB in DRC and the WHO, was published in the New England Journal of Medicine [1]. While this result shows the two epidemics are not linked, it illustrates the speed at which the disease has emerged, says IRD, and it is therefore urgent that we understand just how the disease is spread.

In the study, Centre international de recherches médicales de Franceville (CIRMF) performed whole-genome sequencing of the virus using a high-throughput sequencer that is unique to Sub-Saharan Africa. It confirmed that the virus is from the Ebola species, but different from the one in West Africa. However, it appears to be very similar to those that ravaged in the DRC and Gabon between 1995 and 1997.

Analysis of blood samples in CIRMF, Gabon. Source: CIRMF
Analysis of blood samples in CIRMF, Gabon. Source: CIRMF

This result means that the DRC outbreak is due to a local viral strain, which has been controlled. This epidemic began on 26 July 2014 when a woman fell ill a few days after cutting up a monkey found dead in the forest. To date, 70 cases have been confirmed, including 42 deaths, giving a fatality rate of around 60%, similar to that observed in West Africa. The epidemic peak was observed in the week of 24 August 2014. Thanks to the protection measures implemented by the Congolese health authorities — isolation of patients, protection of medical staff, instructing the populations to avoid all body contact — the epidemic now appears to be contained.

According to IRD, this recent rise in Ebola epidemics shows that the likelihood of the virus being passed on from animal reservoir to humans is increasing. This means there is an urgent need to gain a better understanding of the ways in which the virus circulates (seasonal or other) within its natural reservoir and the factors that govern the virus' transfer from one animal species to another or to humans. Better knowledge of these parameters would enable alert thresholds to be defined and epidemics to be predicted, which could prove invaluable to the rapid implementation of control measures.


1. Maganga GD et al. Ebola Virus Disease in Democratic Republic of the Congo. New England Journal of Medicine, 2014. DOI:10.1056/NEJMoa1411109


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