Published in PLOS One on 2026-06-30, this study is presented as an attributed evidence briefing. The excerpts below are the original researchers’ words, reproduced under their Creative Commons Attribution licence. Health Signal has selected the abstract and, where needed, opening background paragraphs; the complete methods, results, limitations and references remain in the linked paper.
Original authors: Néhémie Nzoyikorera, David F Nieuwenhuijse, Leonard Schuele, Cassien Nduwimana, Armstrong Ndihokubwayo, Théogène Ihorimbere, Denis Niyomwungere, Hayley Cassidy, Marjan Boter, Celestin Nibogora, Richard Molenkamp, Alexis Niyomwungere, Dionis Nizigiyimana, Marie Noelle Uwineza, Idrissa Diawara, Saria Otani, Rogier Bodewes, Frank M Aarestrup, Marion Koopmans, Joseph Nyandwi, Bas B Oude Munnink
Source: PLOS One • DOI 10.1371/journal.pone.0351691
Read the complete primary study ↗ · Creative Commons Attribution licence
From the researchers
Abstract
Despite remarkable progress towards measles elimination in Burundi, the country has seen a resurge in cases since 2019. Epidemiological investigations have been performed; however, it remained unclear if all measles cases involved in recent outbreaks were linked or caused by multiple independent events including introductions from other countries. Therefore, the objective of this study is to investigate the genetic diversity and evolution of measles virus (MeV) during the last large MeV outbreak in Burundi in 2024. The study was carried out on oropharyngeal swab samples collected from four neighboring health districts. Amplicon-based MeV sequencing was performed on the MinION Mk1D. Consensus sequences were generated from 18 isolates and phylogenetic and Bayesian evolution analysis including 152 closely related public genomes were performed. Results showed that all 18 newly generated whole-genome sequences belonged to the genotype B3. Phylogenetic analysis revealed a diverse population of MeV circulating in Burundi, with sequences divided into two separate clusters. The first cluster consisted of two sequences and was most closely related to Italian sequences, while the second cluster was more related to local transmission in the Great-Lakes region based on the N450 region. Based on whole-genome sequences, the remaining 16 whole-genome sequences from Burundi clustered with one sequence from the Netherlands. The most recent common ancestor of the sequences in the second cluster was estimated to be around the beginning of 2023 (between the end of 2022 and the end of 2023 using the 95% confidence intervals) by using Bayesian evolutionary analysis. Here, we provide the first batch of MeV whole-genome sequences generated on the African continent of the ongoing MeV outbreak in the Great Lakes region of Africa. Using these whole genome sequences, we demonstrated that measles viruses genotype B3 were already circulating in Burundi since the beginning of 2023 well before the outbreak in 2024 was noted. We also showed that the recurrent measles outbreaks in Burundi are ignited from different sources, showing that measles in Burundi is sustained by multiple introductions and emphasizing the importance of ongoing molecular surveillance for elimination efforts.
Background
Measles is a highly contagious human disease caused by the measles virus (MeV), a single-stranded negative-sense RNA virus that belongs to the genus Morbillivirus of the Paramyxoviridae family [1,2]. Although MeV is antigenically monotypic, genetic variability in the hemagglutinin (H) and nucleoprotein (N) genes enables the classification of the virus into 24 genotypes (A, B1-B3, C1-C2, D1-D11, E, F, G1-G3, H1-H2). Genotype diversity has been used to monitor progress of measles elimination campaigns and since 2021, only genotypes B3 and D8 have been detected and reported to circulate worldwide [3]. Measles typically causes a red skin rash and is also associated with at least one complication in up to 20–30% of the cases a single complication can be observed [4–6]. The most serious complications include blindness, encephalitis, severe diarrhea, ear infections leading to otitis, and severe respiratory infections such as pneumonia [7].
Reading this evidence
Use the full paper to check the study design, participant selection, comparator and outcome definitions before drawing a practical conclusion. An association does not by itself show cause and effect. A reported performance measure needs its denominator and uncertainty. A finding from a particular facility, sample or time period should retain that scope when it is discussed elsewhere.
This briefing makes the source accessible within the wider public health desk. It does not assess an individual patient or certify a product. When considering relevance to another health system, examine the original authors’ account of context and limitations, then seek local implementation evidence. The related reporting below provides other studies to read alongside this one; it is a topic connection, rather than a claim that their results are directly comparable.
© 2026 Néhémie Nzoyikorera, David F Nieuwenhuijse, Leonard Schuele, Cassien Nduwimana, Armstrong Ndihokubwayo, Théogène Ihorimbere, Denis Niyomwungere, Hayley Cassidy, Marjan Boter, Celestin Nibogora, Richard Molenkamp, Alexis Niyomwungere, Dionis Nizigiyimana, Marie Noelle Uwineza, Idrissa Diawara, Saria Otani, Rogier Bodewes, Frank M Aarestrup, Marion Koopmans, Joseph Nyandwi, Bas B Oude Munnink. Excerpts reproduced under CC BY. Selection, formatting and contextual notes by Health Signal. The researchers are the authors of the source study, not members of Health Signal’s staff.
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