Temporal and spatial analysis of the 2014–2015 Ebola virus outbreak in West Africa (Faculty of Medicine, University of Ljubljana)

Authors:Tatjana Avšič Županc, Miša Korva

The Ebola virus claimed the lives of over 11,000 people during the epidemic in West Africa. The origin of the virus is thought to have been a zoonotic transmission from a bat to a two year-old boy in December 2013. From this index case the virus was spread by human-to-human contact throughout Guinea, Sierra Leone and Liberia. However, the origin of the particular virus in each country and time of transmission was not known, and concerns have been expressed that the virus might be adapting to humans and become more easily transmissible. The authors of the present paper were members of an international team of the European Mobile Laboratory, which was the first diagnostics unit to be deployed to the centre of the outbreak in Guinea.

Deep sequencing of 179 patient samples revealed an epidemiological and evolutionary history of the epidemic from March 2014 to January 2015. The genetic fingerprint of each isolate was defined and compared using complex mathematical modelling that confirmed the virus was introduced into the human population at a single source. An initial lineage A was linked to early Guinean cases, a second lineage B emerged in May/June 2014. As the epidemic expanded, lineage A remained confined in Guinea, but lineage B spread further into Guinea, Liberia and Sierra Leone. Data from the study together with epidemiological information are useful for retrospective testing of the effectiveness of control measures, and they provide an unprecedented window into the evolution of an ongoing viral outbreak. Also, data indicates that the Ebola virus mutated at a lower rate than feared during the recent outbreak, giving hope that new diagnostic methods, treatments and vaccines under development should still be effective in the fight to eradicate the disease.

Source: CARROLL, Miles W., MATTHEWS, David A., HISCOX, Julian A., ELMORE, Michael J., POLLAKIS, Georgios, RAMBAUT, Andrew, KORVA, Miša, AVŠIČ-ŽUPANC, Tatjana, et al. Temporal and spatial analysis of the 2014-2015 Ebola virus outbreak in West Africa. Nature, ISSN 0028-0836., 6. avg. 2015, vol. 524, iss. 7563, str. 97-101, doi: 10.1038/nature14594.