Hosts and transmission of Mycobacterium ulcerans: a systematic review

The control of Buruli ulcer (BU), a debilitating neglected tropical disease, is hampered by the inadequate understanding of the mode of transmission of its causative agent, Mycobacterium ulcerans (M. ulcerans). The DNA of M. ulcerans has been detected in some living organisms and non-living environmental samples of both aquatic and terrestrial sources. However, it is unclear whether the identified organisms support in vivo multiplication of the bacterium or play any role in its transmission. This paper identifies hosts of M. ulcerans, reviews progress made in unravelling the exact mode of transmission of M. ulcerans and identifies research gaps in this aspect of BU epidemiology. Using the search terms, 'niche, Mycobacterium ulcerans' and 'mode of transmission, Mycobacterium ulcerans' as well as defined inclusion criteria, information was obtained from the PubMed database and reviewed to assess their importance to the research question. Aquatic bugs of the genera Appasus and Diplonychus as well as Naucoris cimicoides and possums were identified to support in vivo multiplication of the bacterium. Bite of M. ulcerans contaminated Aedes notoscriptus, bite of aquatic bugs harboring or contaminated with M. ulcerans, and M. ulcerans contaminated skin-puncturing materials present in nature create opportunity for its transmission and infection. Appropriate protective measures may be useful to reduce the risk of exposure to M. ulcerans in BU endemic areas, and incorporation of trophic interactions of aquatic organisms known to support in vivo multiplication of M. ulcerans is needed in future research for better understanding of the spread of M. ulcerans in nature.

Etude des appellations et des representations attachees a l'infection a Mycobacterium ulcerans dans differents pays endemiques d'Afrique

L'objectif de ce travail est de presenter les appellations de l'infection a Mycobacterium ulcerans (ulcere de Buruli) dans les langues africaines et leurs significations. Il vise egalement a explorer les representations attachees a la maladie dans differents pays endemiques d'Afrique. La methodologie utilisee implique l'analyse d' entretiens indivi- duels et de publications scientifiques. Les entretiens individuels ont ete menes aupres de differents chefs de programme et responsables de structures de prise en charge de cette maladie. Les resultats de notre analyse montrent que dans les pays d'Afrique ou l'ulcere de Buruli est endemique (Benin; Cameroun; Congo-Brazzaville; Cote d'Ivoire; Ghana; Ouganda; Republique Democratique du Congo; Sud Soudan et Togo); les appellations de cette maladie peuvent etre classees en trois categories; suivant qu'elles evoquent les origines geographiques de la maladie; les caracteristiques des lesions observees; ou les aspects d'incurabilite et de mystere; en lien avec la sorcellerie. Les representations de cette maladie dans les langues africaines apparaissent identiques et semblent traduire une connaissance relativement bonne de la maladie dans les pays ou l'ulcere de Buruli sevit. L'impact de ces representations influence egalement les types de recours aux soins

Le traitement traditionnel de l'ulcere de Buruli au Benin

The purpose of this tra n s ve rs ve qualitat ive study on traditional treatment for Buruli ulcer in Benin was to track the tre atment itinera ry of pat i e n s ; the main phases of traditional treatment; cost and effi c a cy of such tre atment ; and the knowledge and skills of traditional practitioners. A total of 20 traditional practitioners; 35 patients treated by traditional therapy; and 35 patients treated by surgery were included. Findings showed that both traditional and surgical treatment was sought at a late stage. Reasons determining the type of tre atment chosen included religion; access to adequate care facilities; constraints involved in surgical treatment; duration of hospitalization; and fear of scarring. The four main steps in traditional treatment were diagnosis; removal of necrotic tissue; wound care; and exorcism. The cost of traditional treatment was high not only in c u rre n cy but also by payment in kind (e.g.; live s t o ck and land). Although it is perfo rmed with patient consent; t raditional tre atment presents a number of risks. Information campaigns are necessary to inform populations about available treatments and the possible risks associated with each modality. Care centers must do more to lessen the constraints involved in surgical treatment both in terms of duration of hospitalization and cosmetic outcome

Detection de mycobacterium ulcerans par la technique de polymerase chain reaction (PCR) et relations avec l'etude histopathologique chez des patients porteurs d'ulcerations cutanees chroniques (ulcere de buruli)

"Ce travail est une etude transversale qui avait pour objectif d'etablir les relations entre la detection de Mycobacterium ulcerans par la technique de polymerase Chain reaction (PCR) et l'etude histopathologique chez 33 patients porteurs d'ulcerations cutanees chroniques evoquant cliniquement un ulcere de Buruli. Les methodes d'etude utilisees ont ete pour la biologie moleculaire la technique de ""Single PCR."" par amplification de la sequence d'insertion IS 2404 specifique de Mycobacterium ulcerans et les techniques d'inclusion et coupe en paraffine suivies des colorations a l'hemateine-eosine et au Ziehl-Neelsen pour l'etude histopathologique. Nos resultats ont ete les suivants: *Le taux de positivite de la PCR effectuee sur les fragments biopsiques etait de 90;90pour cent; *Il existait 3 formes histopathologiques: forme necrosante (39;4pour cent); forme mixte (42;4pour cent); forme granulomateuse (18;2pour cent) ; *La comparaison entre les 2 tests diagnostiques a montre que: -Dans la forme necrosante; la PCR et l'histopathologie avaient le meme rendement diagnostique avec un niveau de concordance de 100pour cent. -Dans la forme mixte le niveau de concordance entre les 2 methodes diagnostiques etait de 92;8.6pour cent. -et de 66;67pour cent dans la forme granulomateuse. En conclusion; ces resultats indiquent d'une part un taux de positivite eleve de la PCR realisee sur des fragments tissulaires et d'autre part la fiabilite de l'etude histopathologique pour la confirmation biologique du diagnostic d'ulcere de Buruli dans ses formes necrosante et mixte. En revanche elle devra etre couplee a la PCR pour plus de fiabilite dans les formes granulomateuses."