The projected impact of climate change on the burden of Cryptosporidium in Mali, Kenya, and The Gambia
Megan Kowalcyk, Billy Ogwel, Kristopher B Karnauskas, Henry Badji, Jane Juma, M Jahangir Hossain, Richard Omore, Karen Kotloff, Andrea BuchwaldAbstract
Background
Cryptosporidium is an important cause of moderate-to-severe diarrhea (MSD) among children under five, with the highest burden in Sub-Saharan Africa (SSA). Cryptosporidium is highly climate sensitive, yet there has been no published literature projecting the incidence of Cryptosporidium under climate change in SSA where vulnerability to climate change is highest.
Methods
Utilizing monthly case counts of Cryptosporidium from two case-control studies in The Gambia, Kenya, and Mali, we modeled the relationship between monthly temperature, precipitation, and vulnerability factors with Cryptosporidium incidence by study site using Bayesian Network models. Global climate models were then used to project temperature and precipitation at each site in 2040 and 2055 under two emission scenarios. Future Cryptosporidium incidence was estimated based on projected climate and future vulnerability scenarios.
Results
Global climate models predict increasing temperatures at all sites and increasing rainfall in Kenya under all scenarios. Incidence of Cryptosporidium per 10,000 children is predicted to change by -16.93 (range: -24.84 - 8.92), -4.34 (range: -24.50 - 9.70), and 24.81 (range: 10.41 - 44.06) % in Kenya, Mali, and The Gambia, respectively from baseline (2007 to 2015) to 2055 under high carbon emissions. These estimates are influenced by future vulnerability levels.
Conclusions
The effect of climate change on Cryptosporidium incidence will be location and climate specific, however whether or not vulnerability factors remain stable will have a strong influence on what future Cryptosporidium looks like. Prioritizing development in areas with the highest burden of climate-sensitive health outcomes can mitigate the impact of climate change.