Spatio-temporal patterns and landscape-associated risk of buruli ulcer in Akonolinga, Cameroon

Landier Jordi, Gaudart Jean, Carolan Kevin, Lo Seen Danny, Guégan Jean-François, Eyangoh Sara, Fontanet Arnaud, Texier Gaëtan. 2014. Spatio-temporal patterns and landscape-associated risk of buruli ulcer in Akonolinga, Cameroon. PLoS Neglected Tropical Diseases, 8 (9):e3123, 11 p.

Journal article ; Article de revue à facteur d'impact Revue en libre accès total
Published version - Anglais
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Quartile : Q1, Sujet : TROPICAL MEDICINE / Quartile : Q1, Sujet : PARASITOLOGY

Abstract : Background: Buruli ulcer (BU) is an extensively damaging skin infection caused by Mycobacterium ulcerans, whose transmission mode is still unknown. The focal distribution of BU and the absence of interpersonal transmission suggest a major role of environmental factors, which remain unidentified. This study provides the first description of the spatiotemporal variations of BU in an endemic African region, in Akonolinga, Cameroon. We quantify landscape-associated risk of BU, and reveal local patterns of endemicity. Methodology/Principal Findings: From January 2002 to May 2012, 787 new BU cases were recorded in 154 villages of the district of Akonolinga. Incidence per village ranged from 0 (n = 59 villages) to 10.4 cases/1000 person.years (py); median incidence was 0.4 cases/1,000py. Villages neighbouring the Nyong River flood plain near Akonolinga town were identified as the highest risk zone using the SPODT algorithm. We found a decreasing risk with increasing distance to the Nyong and identified 4 time phases with changes in spatial distribution. We classified the villages into 8 groups according to landscape characteristics using principal component analysis and hierarchical clustering. We estimated the incidence ratio (IR) associated with each landscape using a generalised linear model. BU risk was highest in landscapes with abundant wetlands, especially cultivated ones (IR = 15.7, 95% confidence interval [95%CI] = 15.7[4.2-59.2]), and lowest in reference landscape where primary and secondary forest cover was abundant. In intermediate-risk landscapes, risk decreased with agriculture pressure (from IR[95%CI] = 7.9[2.2-28.8] to 2.0[0.6-6.6]). We identified landscapes where endemicity was stable and landscapes where incidence increased with time. Conclusion/Significance: Our study on the largest series of BU cases recorded in a single endemic region illustrates the local evolution of BU and identifies the Nyong River as the major driver of BU incidence. Local differences along the river are explained by wetland abundance and human modification of the environment. (Résumé d'auteur)

Mots-clés Agrovoc : Maladie de l'homme, Maladie de la peau, Mycobacterium, Évaluation du risque, Paysage, Facteur du milieu, Surveillance épidémiologique, Topographie, couverture du sol, Distribution spatiale

Mots-clés géographiques Agrovoc : Cameroun

Mots-clés complémentaires : mycobacterium ulcerans, Ulcere

Classification Agris : L73 - Animal diseases
000 - Other themes

Champ stratégique Cirad : Axe 4 (2014-2018) - Santé des animaux et des plantes

Auteurs et affiliations

  • Landier Jordi, Institut Pasteur (FRA)
  • Gaudart Jean, Université Aix-Marseille I (FRA)
  • Carolan Kevin, IRD (FRA)
  • Lo Seen Danny, CIRAD-ES-UMR TETIS (FRA) ORCID: 0000-0002-7773-2109
  • Guégan Jean-François, IRD (FRA)
  • Eyangoh Sara, Centre Pasteur du Cameroun (CMR)
  • Fontanet Arnaud, Institut Pasteur (FRA)
  • Texier Gaëtan, Centre Pasteur du Cameroun (CMR)

Source : Cirad - Agritrop (

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