Meningitis is a serious disease. It is an inflammation of the meninges (thin membranes that envelop the brain and spinal cord). In 2021, according to the Meningitis Progress Tracker, meningitis caused about 214,000 deaths of all ages. Children under five accounted for 43 per cent of these deaths, making meningitis the fifth leading infectious cause of child mortality.

Scientists have sought to examine the link between meningitis and the environment. It has been observed that high temperatures (>39.5°C) and the high concentration of dust in the air are also significant risk factors in the increase in the number of cases during meningitis epidemics. The work of Jean-Marc Collart and Jean François Jusot published in The Journal of Allergy and Clinical Immunology (https://www.jacionline.org/article/S0091-6749(16)30616-9/fulltext ) presents this relationship between meningitis and climatic variations in Sub-Saharan Africa. This suggests that climate change could influence the frequency and geographic distribution of disease outbreaks.

"Climate change is affecting the evolution of meningitis in West Africa, more specifically in Côte d'Ivoire. Over the past 20 years, a high number of cases of meningitis has been increasingly observed in central and southern Côte d'Ivoire, while cases are usually more recurrent in the northern part of the country. This could be due to a change in climatic parameters, making these regions more favourable to the transmission of meningitis. ", explains Axelle Tano, associate researcher at the Swiss Centre for Scientific Research in Côte d'Ivoire (CSRS) in her master's thesis on the theme: "Contribution of satellite data to the spatio-temporal modelling of the epidemiology of meningitis in West Africa in a context of climate change: The case of Côte d'Ivoire."

The change in the geographical distribution of meningitis due to climate change is confirmed by Molly Cliff in her study entitled "Re-examining the meningitis belt: associations between environmental factors and the risk of meningitis epidemics in Africa" (https://www.medrxiv.org/content/10.1101/2025.02.25.25322867v1.full)

"Seasonality and climate variability have a key influence on the spatiotemporal distribution of bacterial meningitis. During the dry season from December to April, initially dominated by Harmattan winds and increased dust concentration, the incidence of the disease can reach 800 cases per 100,000 people. »

In doing so, the current African meningitis belt comprising 26 countries could expand to other countries if nothing is done. "The proposed expansion of the meningitis belt in line with this, to Togo, the Central African Republic, Cameroon and Côte d'Ivoire was consistent with regional environmental changes. Changes in land use, combined with climatic factors, have potentially led to a reduction in humidity combined with an increase in dust, favouring epidemic conditions. »

Modelling as a crucial aid in the fight against

Epidemiological modelling is now a strategic tool in the fight against diseases. By simplifying reality, it makes it possible to simulate different scenarios and anticipate risks. Indeed, modeling is a process that consists of creating a simplified representation of a real phenomenon using mathematical formulas, data, and simulations. It makes it possible to understand, analyze and above all predict the behavior of this phenomenon in different situations. For example, in the case of meningitis, the evolution of the disease can be modelled by taking into account factors such as climate, population density or vaccination coverage. It thus becomes a strategic lever for preventing meningitis epidemics and protecting the most exposed populations.

"Modelling allows us to understand the dynamics of the disease and its link with climatic parameters. It can also be useful for predicting the presence of the disease or the risk of transmission," says Axelle.