The role of environmental and individual factors in the social epidemiology of chikungunya disease on Mayotte Island

This article examines the role of environmental and individual factors in the social epidemiology of chikungunya disease on the island of Mayotte (South-western Indian Ocean). In an epidemic setting, an interdisciplinary study combining interviews, observations, and serological tests was conducted to: (1) estimate the frequency and social distribution of chikungunya disease and (2) identify its principal cognitive, behavioral, and environmental determinants within a stratified random sample of the Mayotte population (n=888). Semi-parametric tests and multiple correspondence analyses were used to describe the statistical relationships between the different classes of variables examined in this study and the presence of antibodies attributable to chikungunya. These analyses highlighted differences between two main types of populations: one more autochthonous, more urban and better educated population, which shared 'legitimate' representations of the disease-from a biomedical viewpoint; and the other more migrant, more suburban, and more deprived, which is characterized by folk theories of chikungunya virus infection. Moreover, a series of logistic regression models revealed that social disparities in the distribution of virus infection were primarily structured by the housing conditions and cognitive representations of the disease held by the participants. These results suggest that environmental and individual factors are equally crucial in epidemic settings, and that they could explain, to a considerable extent, the social differences observed in morbidity associated with recent emerging infectious diseases in tropical countries.