PCR-confirmed Buruli ulcer incidence over a 16-year period in Benin: a nationwide, retrospective, observational study
Abstract
BACKGROUND: Buruli ulcer is a neglected tropical disease caused by Mycobacterium ulcerans, primarily affecting rural populations in west and central Africa. Between 2004 and 2023, reported Buruli ulcer cases declined sharply across the continent from 5871 to 1573. Determining whether this decline reflects real epidemiological change or surveillance artifacts is crucial for global Buruli ulcer control. We aimed to quantify the incidence of Buruli ulcer in Benin, to analyse observed epidemiological changes, and to relate them to environmental and climate changes. METHODS: We did a nationwide, retrospective, observational study using data recorded by Benin's National Buruli Ulcer Control Programme at four specialised health-care centres in southern Benin over 16 years (2008-24). Data were collected prospectively at the time of patient care. 2568 patients with PCR-confirmed Buruli ulcer were included. Annual incidence trends were examined by age, sex, municipality, and clinical form of the lesion. Environmental and climatic variables, including water surface area, temperature, urbanisation, and land use, were integrated with patient data to assess ecological associations. In parallel, a large-scale environmental survey investigated the presence of M ulcerans DNA in aquatic ecosystems. Data census and population projections were obtained from the National Institute of Statistics and Demography of Benin; environmental variables were derived from spatial analyses conducted using open-access geospatial databases. FINDINGS: The incidence of Buruli ulcer decreased by nearly 80% during the study period, from 1·37 per 10 000 inhabitants (SD 0·21 per 10 000 inhabitants) in 2010-16 to 0·24 per 10 000 inhabitants in 2024, with the steepest decrease in children aged 15 years and younger. Historical age and sex differences in incidence largely disappeared over the period. The decrease in incidence coincided with a 25-30% reduction in open water surfaces and a more than 1°C rise in mean air temperature. M ulcerans DNA was undetectable in 122 aquatic sites sampled between 2021 and 2024. INTERPRETATION: To our knowledge, this study provides the first comprehensive, country-wide evidence of a sustained decline in Buruli ulcer incidence in Africa. Environmental changes, particularly climate warming and water surface reduction, might have contributed to this trend. Continued surveillance is essential to confirm whether Buruli ulcer foci are disappearing and to ensure early detection of potential re-emergence. FUNDING: French Ministry of Higher Education through the Doctoral School of Biology and Health, University of Angers, the French National Research Agency, and INSERM.
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BibTeX
@article{johnson2026pcrconfirmed,
title = {{PCR-confirmed Buruli ulcer incidence over a 16-year period in Benin: a nationwide, retrospective, observational study}},
author = {Harvey Johnson and Télésphore Brou and Esaïe Anagonou and Gérard Kpoton and Marie Robbe-Saule and Franck Mignawande and Jean Gabin Houezo and Delphin Degla and Yves Barogui and Julia Aguia and Christian Steunou and Line Ganlonon and Akimath Habib and Perrin Catraye and Lotus Hotegni and Ange Dossou and Caroline Baumy and Alexandra Boccarossa and Sébastien Fleuret and Vincent Dubee and Estelle Marion and Matthieu Eveillard and Laurent Marsollier and Ghislain Emmanuel Sopoh},
journal = {The Lancet global health},
year = {2026},
month = nov,
doi = {10.1016/j.langlo.2026.104017},
url = {https://univ-reunion.hal.science/hal-05854410v1},
note = {CC BY-NC},
}
RIS
TY - JOUR
TI - PCR-confirmed Buruli ulcer incidence over a 16-year period in Benin: a nationwide, retrospective, observational study
AU - Harvey Johnson
AU - Télésphore Brou
AU - Esaïe Anagonou
AU - Gérard Kpoton
AU - Marie Robbe-Saule
AU - Franck Mignawande
AU - Jean Gabin Houezo
AU - Delphin Degla
AU - Yves Barogui
AU - Julia Aguia
AU - Christian Steunou
AU - Line Ganlonon
AU - Akimath Habib
AU - Perrin Catraye
AU - Lotus Hotegni
AU - Ange Dossou
AU - Caroline Baumy
AU - Alexandra Boccarossa
AU - Sébastien Fleuret
AU - Vincent Dubee
AU - Estelle Marion
AU - Matthieu Eveillard
AU - Laurent Marsollier
AU - Ghislain Emmanuel Sopoh
PY - 2026
DA - 2026/11/06
JO - The Lancet global health
DO - 10.1016/j.langlo.2026.104017
UR - https://univ-reunion.hal.science/hal-05854410v1
AB - BACKGROUND: Buruli ulcer is a neglected tropical disease caused by Mycobacterium ulcerans, primarily affecting rural populations in west and central Africa. Between 2004 and 2023, reported Buruli ulcer cases declined sharply across the continent from 5871 to 1573. Determining whether this decline reflects real epidemiological change or surveillance artifacts is crucial for global Buruli ulcer control. We aimed to quantify the incidence of Buruli ulcer in Benin, to analyse observed epidemiological changes, and to relate them to environmental and climate changes. METHODS: We did a nationwide, retrospective, observational study using data recorded by Benin's National Buruli Ulcer Control Programme at four specialised health-care centres in southern Benin over 16 years (2008-24). Data were collected prospectively at the time of patient care. 2568 patients with PCR-confirmed Buruli ulcer were included. Annual incidence trends were examined by age, sex, municipality, and clinical form of the lesion. Environmental and climatic variables, including water surface area, temperature, urbanisation, and land use, were integrated with patient data to assess ecological associations. In parallel, a large-scale environmental survey investigated the presence of M ulcerans DNA in aquatic ecosystems. Data census and population projections were obtained from the National Institute of Statistics and Demography of Benin; environmental variables were derived from spatial analyses conducted using open-access geospatial databases. FINDINGS: The incidence of Buruli ulcer decreased by nearly 80% during the study period, from 1·37 per 10 000 inhabitants (SD 0·21 per 10 000 inhabitants) in 2010-16 to 0·24 per 10 000 inhabitants in 2024, with the steepest decrease in children aged 15 years and younger. Historical age and sex differences in incidence largely disappeared over the period. The decrease in incidence coincided with a 25-30% reduction in open water surfaces and a more than 1°C rise in mean air temperature. M ulcerans DNA was undetectable in 122 aquatic sites sampled between 2021 and 2024. INTERPRETATION: To our knowledge, this study provides the first comprehensive, country-wide evidence of a sustained decline in Buruli ulcer incidence in Africa. Environmental changes, particularly climate warming and water surface reduction, might have contributed to this trend. Continued surveillance is essential to confirm whether Buruli ulcer foci are disappearing and to ensure early detection of potential re-emergence. FUNDING: French Ministry of Higher Education through the Doctoral School of Biology and Health, University of Angers, the French National Research Agency, and INSERM.
SN - 2572-116X
SN - 2214-109X
ER -