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Impacts on health

One of the aims of AMMA is to study the West African Monsoon (WAM) public health impacts, focusing epidemics of meningitis and malaria.

Scientists involved with geophysics and public health study the relationship between intra-seasonal, seasonal and interannual climate variability and these epidemics in this belt.

An objective of AMMA is to evaluate the impact of WAM on the dynamics of meningitis and malaria by identifying the roles of winds, dust concentration, precipitation, temperature, humidity and some environmental variables in morbidity, diseases and mosquito density data at selected locations.

Another objective is to combine climate research and health sciences, for defining epidemiological monitoring for early warning of epidemics over WAM to contribute to limit their impact.

Meningitis

In the Sahel belt (Senegal, Mali, Burkina-Faso and Niger), a meningococcal meningitis epidemic affects every year 25 000 to 200 000 people during the dry season within the Meningitis Belt (10-15N).

Using statistical methods, AMMA researchers have recently produced the first quantified description of this relationship using epidemiological data over 9 years:
the start of epidemics coincides with the Harmattan winter maximum;
the end with a recession in Harmattan in the sixteenth week of the calendar year.

These results do not provide a direct link between the intensity of winter and the size of epidemics but should be useful for the development of epidemiological early-warning systems in this region, in order to prevent epidemics and try to limit their effect.
Current research focuses on the statistical description of multi-year data collections of meningitis, on simulations of dust concentrations from December to May for 5 years and on the validation of Satellite products for better investigating the links between dust concentration and epidemiology, then producing statistical forecasts.

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Malaria

Malaria is the major of cause of mortality (1 million / year in tropical Africa). Malaria epidemics occur during the rainy season when the mosquito density increases drastically in response to precipitation, temperature and humidity.

Using both statistical and numerical methods, AMMA researchers are using datasets collected in various WA villages for describing the impact of climate variability during the rainy season on the density of vectors (Anopheles gambiae).

Mosquitoes were captured on human bait and indoor spraying. The focus is on intra-seasonal variability including surges and breaks during the rainy season to calibrate a model of anopheles and to predict epidemics (start, end, intensity).
Weekly averages of person-biting rate were found partly dependant to some climatic thresholds parameters: in particular the first attack of Anopheles gambiae occurs always under particular conditions of relative humidity.
Diagnostics and forecasts are currently improving using other environmental predictors such as soil wetness, river discharge ....

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Anophele gambiae, vector of malaria.
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