1In the early 2000s, a team working in Mali made a surprising discovery: there is a link between the occurrence of the Harmattan, a hot and dry wind from the Sahara, and meningitis outbreaks. This finding led researchers to study the two countries most affected by annual meningitis epidemics, i.e. Niger and Burkina Faso.

Aedes aegypti, dengue vector mosquito.

2By correlating epidemiological data collected since the late 1960s with the weather information available, they showed that 25% of the observed variability of meningitis cases are linked to wind intensity. This can be used to better anticipate the occurrence of major epidemics such as that of 1996, which cost 25,000 lives.

Sandstorm, Burkina Faso.

3A few years later, in 2009, a multidisciplinary team initiated similar research in New Caledonia. The idea this time was to study fluctuations in dengue fever outbreaks. Researchers studied 40 years of epidemiological data, from 1971 to 2011, and showed evidence of very close statistical relationships between climatic temperature and rainfall variables and disease outbreaks. They also highlighted the possibility of predicting epidemics one month in advance using a statistical model with a 70% to 80% reliability rate. This model is currently used in decision-making processes and helps health authorities anticipate these epidemics, by informing populations, forecasting insecticide orders and organising the vector control strategy. Looking ahead to 2100, it suggests that, due to climate change, the frequency of dengue fever epidemics could increase from once every five years to once a year.