Defining and targeting high-risk populations in Buruli ulcer
Authors: Jordi Landier, Arnaud Fontanet, Gaëtan Texier
Journal: The Lancet Global Health (2014)

In their article in The Lancet Global Health, Quentin Vincent and colleagues (July issue)1Vincent QB Ardant MF Adeye A et al.Clinical epidemiology of laboratory-confirmed Buruli ulcer in Benin: a cohort study.Lancet Glob Health. 2014; 2: e422-e430Summary Full Text Full Text PDF Scopus (74) Google Scholar analysed 1227 laboratory-confirmed cases of Buruli ulcer and provided clinically relevant results such as an operational classification of lesions. They reported unbalanced age and sex groups, as previously noted,2Debacker M Aguiar J Steunou C et al.Mycobacterium ulcerans disease: role of age and gender in incidence and morbidity.Trop Med Int Health. 2004; 9: 1297-1304Crossref PubMed Scopus (73) Google Scholar and an over-representation of Buruli ulcer cases in children. Quantification of this over-representation is challenging—proper comparisons between age groups need estimation of age-specific incidence rates, which are rarely reported.2Debacker M Aguiar J Steunou C et al.Mycobacterium ulcerans disease: role of age and gender in incidence and morbidity.Trop Med Int Health. 2004; 9: 1297-1304Crossref PubMed Scopus (73) Google Scholar, 3Revill WLD Barker DJP Seasonal distribution of mycobacterial skin ulcers.Brit J Prev Soc Med. 1972; 26: 23-27PubMed Google Scholar Furthermore, most studies of risk factors rely on age-matched and sex-matched case-control designs, precluding comparative analysis by age and sex.4Jacobsen KH Padgett JJ Risk factors for Mycobacterium ulcerans infection.Int J Infect Dis. 2010; 14: e677-e681Summary Full Text Full Text PDF PubMed Scopus (54) Google Scholar Here we report incidence rates for men and women by 5 year age-groups for 814 laboratory-confirmed cases in the Nyong River region in Cameroon (figure). Estimates were obtained using Buruli ulcer surveillance data from the Centre Pasteur du Cameroun (National Reference Laboratory for Mycobacteria, Yaoundé, Cameroon) from 2002 to 2012, and detailed 2010 population census data. Incidence rate was twice as high for children aged 5–14 years (165 per 100 000 person-years) as for adults older than 15 years (87 per 100 000 person-years). Incidence rate was stable among adults, suggesting lifelong exposure and possibly increasing susceptibility to disease development among older individuals. The overall women–men incidence rate ratio was 1·01 (95% CI 0·88–1·15). Incidence rate ratio was 0·81 (0·67–0·98) for children aged 0–14 years, 1·55 (1·22–1·98) for adults aged 15–49 years, and 0·85 (0·57–1·28) for adults older than 50 years. Vincent and colleagues1Vincent QB Ardant MF Adeye A et al.Clinical epidemiology of laboratory-confirmed Buruli ulcer in Benin: a cohort study.Lancet Glob Health. 2014; 2: e422-e430Summary Full Text Full Text PDF Scopus (74) Google Scholar defined age-specific and sex-specific subgroups relevant for clinical considerations.1Vincent QB Ardant MF Adeye A et al.Clinical epidemiology of laboratory-confirmed Buruli ulcer in Benin: a cohort study.Lancet Glob Health. 2014; 2: e422-e430Summary Full Text Full Text PDF Scopus (74) Google Scholar We define three subgroups—boys younger than 15 years, women aged 15–50 years, and elderly people—which are likely to have different exposures, behaviours, immunity, and treatment-seeking attitudes. We advocate that this risk categorisation is relevant for epidemiological studies and public health programmes such as prevention or case-detection campaigns. We declare no competing interests. Clinical epidemiology of laboratory-confirmed Buruli ulcer in Benin: a cohort studyOur findings have important clinical implications for daily practice, including enhanced surveillance for early detection of osteomyelitis in boys; systematic search for M ulcerans in osteomyelitis cases of non-specific aspect in areas endemic for Buruli ulcer; and specific disability prevention for patients presenting with osteomyelitis, oedema, or multifocal or large lesions. Our findings also suggest a crucial underestimation of the burden of Buruli ulcer in Africa and raise key questions about the contribution of environmental and physiopathological factors to the recorded heterogeneity of the clinical presentation of Buruli ulcer. Full-Text PDF Open AccessDefining and targeting high-risk populations in Buruli ulcer–Authors' replyWe thank Jordi Landier and colleagues for their comments about our recent Article in The Lancet Global Health.1 In their work, Landier and coworkers generalise some of our observations on Buruli ulcer in Benin to those for Cameroon, the country that has the fifth highest prevalence of Buruli ulcer worldwide. Briefly, they make use of age and sex distribution from the Cameroon national census to show that patients aged 5–14 years were twice as likely to be affected by Buruli ulcer as older individuals; and that boys were over-represented in individuals younger than 15 years, women were over-represented in patients aged 15–50 years, and that men and women were equally represented in patients older than 50 years. Full-Text PDF Open Access