Research Article: Risk Factors for Buruli Ulcer: A Case Control Study in Cameroon

Date Published: December 19, 2007

Publisher: Public Library of Science

Author(s): Régis Pouillot, Gonçalo Matias, Christelle Mbondji Wondje, Françoise Portaels, Nadia Valin, François Ngos, Adelaïde Njikap, Laurent Marsollier, Arnaud Fontanet, Sara Eyangoh, Pamela Small

Abstract: BackgroundBuruli ulcer is an infectious disease involving the skin, caused by Mycobacterium ulcerans. This disease is associated with areas where the water is slow-flowing or stagnant. However, the exact mechanism of transmission of the bacillus and the development of the disease through human activities is unknown.Methodology/Principal FindingsA case-control study to identify Buruli ulcer risk factors in Cameroon compared case-patients with community-matched controls on one hand and family-matched controls on the other hand. Risk factors identified by the community-matched study (including 163 pairs) were: having a low level of education, swamp wading, wearing short, lower-body clothing while farming, living near a cocoa plantation or woods, using adhesive bandages when hurt, and using mosquito coils. Protective factors were: using bed nets, washing clothes, and using leaves as traditional treatment or rubbing alcohol when hurt. The family-matched study (including 118 pairs) corroborated the significance of education level, use of bed nets, and treatment with leaves.Conclusions/SignificanceCovering limbs during farming activities is confirmed as a protective factor guarding against Buruli ulcer disease, but newly identified factors including wound treatment and use of bed nets may provide new insight into the unknown mode of transmission of M. ulcerans or the development of the disease.

Partial Text: Buruli ulcer (BU) is an infectious disease involving the skin, caused by Mycobacterium ulcerans, characterized by a painless nodule, papule, plaque or edema, evolving into a painless ulcer with undermined edges, often leading to disabling sequelae [1]. BU has been reported from 30 countries in Africa, the Americas, Asia and the Western Pacific, mainly in tropical and subtropical regions [2],[3]. The epidemiologic pattern is defined by the presence of confined foci where BU is endemic [1],[3], with prevalence ranging from a few cases to up to 22% in given communities [4]. The preventive and therapeutic tools for reducing the impact of this disease are still very limited [5],[6].

We enrolled 163 probable cases, 163 community-matched controls and 118 familial controls.

This case-control study identifying BU risk factors in Cameroon is the first published.

Our findings are consistent with both major hypotheses of M. ulcerans transmission, i.e. insect bites and/or contamination following or accompanying trauma. Treatment practices following trauma were highly significant, supporting the hypothesis involving contamination of a trauma site. However, the use of bed nets, which we propose to be a protective factor, favors the hypothesis involving an insect vector. A specific study should be undertaken to confirm these risk factors for two reasons. First, it may yield information about the mode of transmission. Second, measures to control these risks should be easy to implement to protect inhabitants from BU and other diseases.



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