Scientists running laboratory clinical trial procedures in a laboratory at UVRICredit: Uganda Virus Research Institute (UVRI)

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As climate change makes some regions in Africa more conducive to the ticks that carry Crimean-Congo Hemorrhagic Fever (CCHF), a new risk map is providing information that could strengthen surveillance strategies and speed up response to the disease.

CCHF is transmitted to humans through tick bites or through contact with the bodily fluids of infected animals or people. Although the virus does not make animals sick, it remains active in their bloodstreams for up to a week. There is no cure and the fatality rate is up to 40%.

Researchers from the International Livestock Research Institute, led by Abdoul Kader Ilboudo, analysed decades of outbreak data to pinpoint regions most vulnerable to future infections. The study, published in Scientific Reports,1 underscores the need for better disease surveillance since public health systems in these areas often lack resources to monitor and control outbreaks.

Factors like population density and land cover types contribute to outbreaks, while areas with higher rainfall and cooler temperatures appear to be less affected.The researchers warn that, as climate and land use change, these risk zones may shift, making early detection and prevention crucial.

The probability of a CCHF outbreak was found to be higher than 75% in countries such as Mauritania, Senegal, and Mali in West Africa, South Sudan, Sudan, and Chad in Central Africa, Uganda and Kenya in East Africa, as well as South Africa, Botswana and Namibia in the South. The risk is less than 10% along the Gulf of Guinea and less than 1% in most of the Democratic Republic of Congo, Republic of Congo, and Gabon.

The study used historical outbreak data from 1981 to 2022, focusing on nine SSA countries, and Bayesian modeling to produce their detailed risk map.

The study also indicates that regions with high livestock density often face increased risks due to human exposure to ticks during farming or herding activities.