Impact of Climate Change on Mycetoma Distribution and Etiology in Senegal: The Role of Reduced Rainfall

Abstract

Aims:  To check whether climate change, through a drop in rainfall, has led to an increase in the range of mycetomas in Senegal and to verify if eumycetomas occur with predilection in the most arid areas with low rainfall. Methodology: we conducted a retrospective, descriptive study in which all cases of mycetoma (2000-2022) followed up in the dermatology and orthopaedics referral units of the country's university hospital centres and hospitals in endemic areas were collected. Data on isohyets (1947-2022) were provided by the Agence Nationale de l'Aviation Civile et de la Météorologie. Analyses were performed with SPSS version 18. All p ≤0.05 were considered statistically significant. Results: Analysis of precipitation showed a decrease of 200 mm in the national average.  The 800 isohyets moved southwards.   With 291 cases, we observed a widening of the range of mycetomas in Senegal, with cases located in areas receiving more than 800 mm of rainfall. Fungal mycetomas accounted for almost half of the cases (49.8%, n=155) and were more likely to have black grains and were statistically correlated with rainfall of less than 400 mm (P=0.002), corresponding to the northern zone. Actinomycetoma was more frequent above 400 mm, with 60% (p=0.002). Conclusion: Climate change has extended the range of mycetomas in Senegal by reducing rainfall. The fungal forms are becoming more common and predominate in arid zones with rainfall of less than 400 mm. The rise of eumycetomas is worrying because efforts to treat eumycetoma are limited and would benefit from scaling up, as existing treatments are inaccessible, expensive and not universally covered by international organisations or ministerial disease control programmes.