l'article du mois (Janvier 2013)
by Agier L, Deroubaix A,Martiny N, Yaka P, Djibo A, Broutin H.
J R Soc Interface 10: 20120814.
http://dx.doi.org/10.1098/rsif.2012.0814
Bacterial meningitis is an ongoing threat for the population of the African
Meningitis Belt, a region characterized by the highest incidence rates worldwide.
The determinants of the disease dynamics are still poorly understood;
nevertheless, it is often advocated that climate and mineral dust have a large
impact. Over the last decade, several studies have investigated this relationship
at a large scale. In this analysis, we scaled down to the district-level
weekly scale (which is used for in-year response to emerging epidemics),
and used wavelet and phase analysis methods to define and compare the
time-varying periodicities of meningitis, climate and dust in Niger. We
mostly focused on detecting time-lags between the signals that were consistent
across districts. Results highlighted the special case of dust in
comparison to wind, humidity or temperature: a strong similarity between
districts is noticed in the evolution of the time-lags between the seasonal
component of dust and meningitis. This result, together with the assumption
of dust damaging the pharyngeal mucosa and easing bacterial invasion,
reinforces our confidence in dust forcing on meningitis seasonality. Dust
data should now be integrated in epidemiological and forecasting models
to make them more realistic and usable in a public health perspective.
