Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
Because many biological processes related to the dynamics of infectious diseases are caused by complex interactions between the environment, the host(s) and the agent(s), the necessity to address the methodological implications of this inherent complexity has recently emerged in epidemiology. Most epidemiologists now acknowledge that most human infectious diseases are likely to have complex dynamics. However, this knowledge still percolates with difficulty in their statistical "modus operandi". Indeed, for the study of complex systems, the traditional first-line statistical toolbox of epidemiologists (mainly built around the Generalized Linear Model family), despite its undeniable practicality and robustness, has structural limitations deprecating its usefulness. Three major sources of complexity neglected or not taken into account by this first-line statistical toolbox and having deep statistical implications are the multi-level organization of data, the non-linear relationships between variables and the complex interactions between variables. Three promising candidates to incorporate along with traditional tools for a new first-line statistical toolbox more suitable to apprehend these sources of complexity are the generalized linear mixed models, the generalized additive models, and the structural equation models. The aforementioned methodologies have the advantage to be generalizations of GLM models and are relatively easy to implement. Their assimilation and implementation would thus be greatly facilitated for epidemiologists. More globally, this text underlines that an improved use of other methods as such described here compared to traditional ones has to be performed to better understand the complexity challenging epidemiologists every day. This is particularly true in the field of infectious diseases for which major public health challenges will have to be addressed in the coming decades.
ISSN: 1567-1348

inserm-00872354
http://www.hal.inserm.fr/inserm-00872354
http://www.hal.inserm.fr/inserm-00872354/document
http://www.hal.inserm.fr/inserm-00872354/file/main_document.pdf
DOI : 10.1016/j.meegid.2013.09.006

Éditeur(s) : HAL CCSD Centers for Disease Control and Prevention
Résumé : International audience
To determine when risk for Buruli ulcer is highest, we examined seasonal patterns in a highly disease-endemic area of Cameroon during 2002-2012. Cases peaked in March, suggesting that risk is highest during the high rainy season. During and after this season, populations should increase protective behaviors, and case detection efforts should be intensified.
ISSN: 1080-6040

Droits : http://creativecommons.org/licenses/by-nc-nd/
hal-01307147
https://hal-amu.archives-ouvertes.fr/hal-01307147
https://hal-amu.archives-ouvertes.fr/hal-01307147/document
https://hal-amu.archives-ouvertes.fr/hal-01307147/file/14-1336.pdf
DOI : 10.3201/eid2108.141336

Éditeur(s) : HAL CCSD
Résumé : International audience
Background Mycobacterium ulcerans infection is the third most common mycobacterial disease in the world after tuberculosis and leprosy. To date, transmission pathways from its environmental reservoir to humans are still unknown. In South America, French Guiana has the highest reported number of M ulcerans infections across the continent. This empirical study aimed to characterise the epidemiology of M ulcerans infection in French Guiana between 1969 and 2013.MethodsData were collected prospectively mainly by two dermatologists at Cayenne Hospital’s dermatologydepartment between Jan 1, 1969, and Dec 31, 2013, for age, date of diagnosis, sex, residence, location of the lesion,type of lesion, associated symptoms, and diagnostic method (smear, culture, PCR, or histology) for all confirmed andsuspected cases of M ulcerans. We obtained population data from censuses. We calculated mean M ulcerans infectionincidences, presented as the number of cases per 100 000 person-years.Findings 245 patients with M ulcerans infections were reported at Cayenne Hospital’s dermatology department duringthe study period. M ulcerans infection incidence decreased over time, from 6·07 infections per 100 000 person-years(95% CI 4·46–7·67) in 1969–83 to 4·77 infections per 100 000 person-years (3·75–5·79) in 1984–98 and to3·49 infections per 100 000 person-years (2·83–4·16) in 1999–2013. The proportion of children with infections alsodeclined with time, from 42 (76%) of 55 patients in 1969–83 to 26 (31%) of 84 in 1984–98 and to 22 (21%) of 106 in1999–2013. Most cases occurred in coastal areas surrounded by marshy savannah (incidence of 21·08 per100 000 person-years in Sinnamary and 21·18 per 100 000 person-years in Mana). Lesions mainly affected limbs (lowerlimbs 161 [66%] patients; upper limbs 60 [24%] patients). We diagnosed no bone infections.Interpretation The decrease of M ulcerans infection incidence and the proportion of children with infections over a45 year period in this ultra-peripheral French territory might have been mostly driven by improving living conditions,prophylactic recommendations, and access to health care.
The Lancet Planetary Health

inserm-01545603
http://www.hal.inserm.fr/inserm-01545603
http://www.hal.inserm.fr/inserm-01545603/document
http://www.hal.inserm.fr/inserm-01545603/file/2017%2C%20Douine%20-%20Mycobacterium%20ulcerans%20infection%20%28Buruli%20ulcer%29.pdf
http://www.hal.inserm.fr/inserm-01545603/file/Comments.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
Many emerging infectious diseases are caused by generalist pathogens that infect and transmit via multiple host species with multiple dissemination routes, thus confounding the understanding of pathogen transmission pathways from wildlife reservoirs to humans. The emergence of these pathogens in human populations has frequently been associated with global changes, such as socio-economic, climate or biodiversity modifications, by allowing generalist pathogens to invade and persist in new ecological niches, infect new host species, and thus change the nature of transmission pathways. Using the case of Buruli ulcer disease, we review how land-use changes, climatic patterns and biodiversity alterations contribute to disease emergence in many parts of the world. Here we clearly show that Mycobacterium ulcerans is an environmental pathogen characterized by multi-host transmission dynamics and that its infectious pathways to humans rely on the local effects of global environmental changes. We show that the interplay between habitat changes (for example, deforestation and agricultural land-use changes) and climatic patterns (for example, rainfall events), applied in a local context, can lead to abiotic environmental changes and functional changes in local biodiversity that favor the pathogen’s prevalence in the environment and may explain disease emergence.
ISSN: 2222-1751

Droits : http://creativecommons.org/licenses/by/
hal-01528488
http://hal.upmc.fr/hal-01528488
http://hal.upmc.fr/hal-01528488/document
http://hal.upmc.fr/hal-01528488/file/emi20177a.pdf
DOI : 10.1038/emi.2017.7