Comparative study of meningitis dynamics across nine African countries: a global perspective

Hélène Broutin,Marie-Françoise Courel,Benjamin Sultan,Guillaume Constantin De Magny,Solenne Philippon,Jean-François Guégan

doi:10.1186/1476-072x-6-29

Abstract

BackgroundMeningococcal meningitis (MM) represents an important public health problem especially in the "meningitis belt" in Africa. Although seasonality of epidemics is well known with outbreaks usually starting in the dry season, pluri-annual cycles are still less understood and even studied. In this context, we aimed at study MM cases time series across 9 sahelo-sudanian countries to detect pluri-annual periodicity and determine or not synchrony between dynamics. This global and comparative approach allows a better understanding of MM evolution in time and space in the long-term.ResultsWe used the most adapted mathematical tool to time series analyses, the wavelet method. We showed that, despite a strong consensus on the existence of a global pluri-annual cycle of MM epidemics, it is not the case. Indeed, even if a clear cycle is detected in all countries, these cycles are not as permanent and regular as generally admitted since many years. Moreover, no global synchrony was detected although many countries seemed correlated.ConclusionThese results of the first large-scale study of MM dynamics highlight the strong interest and the necessity of a global survey of MM in order to be able to predict and prevent large epidemics by adapted vaccination strategy. International cooperation in Public Health and cross-disciplines studies are highly recommended to hope controlling this infectious disease.

Highlights

Meningococcal meningitis (MM) represents an important public health problem especially in the "meningitis belt" in Africa
(page number not for citation purposes) http://www.ij-healthgeographics.com/content/6/1/29 with Niger till the end of the 60's and both dynamics become synchronous (Figure 2-D). All these results show that meningitis dynamics are out of phase in these 4 countries but that pluri-annual epidemics become more synchronous since the end of the 60's and the beginning of the 70's
We found a high correlation in MM dynamics between the countries, even if these correlations are not permanent in time

Summary

Introduction

Meningococcal meningitis (MM) represents an important public health problem especially in the "meningitis belt" in Africa. Seasonality of epidemics is well known with outbreaks usually starting in the dry season, pluri-annual cycles are still less understood and even studied In this context, we aimed at study MM cases time series across 9 sahelo-sudanian countries to detect pluri-annual periodicity and determine or not synchrony between dynamics. The global idea is to compare longterm series of disease cases across localities and countries so as to characterize the evolution of epidemics periodicity and to determine the existence of synchrony between time series Such an approach should considerably improve our understanding of trends in global disease dynamics and facilitate the emergence of predictive and quantitative tools for vaccination programs [6]. Social interactions (e.g. pilgrims), transmission of more virulent serotypes (e.g. recent spread of the W135 serotype in Africa), and susceptibility of populations constitute the major favourable drivers of resurgence and dispersion of the disease

Methods

Results

Discussion

Conclusion