The global distribution of Crimean-Congo hemorrhagic fever

Abstract

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne infection caused by a virus (CCHFV) from the Bunyaviridae family. Domestic and wild vertebrates are asymptomatic reservoirs for the virus, putting animal handlers, slaughterhouse workers, and agricultural laborers at highest risk in endemic areas, with secondary transmission possible through contact with infected blood and other bodily fluids. Human infection is characterized by severe symptoms that often result in death. While it is known that CCHFV transmission is limited to Africa, Asia, and Europe, definitive global extents and risk patterns within these limits have not been well described.

Methods

We used an exhaustive database of human CCHF occurrence records and a niche modeling framework to map the global distribution of risk for human CCHF occurrence.

Results

A greater proportion of shrub or grassland cover was the most important contributor to our model, which predicts highest levels of risk around the Black Sea, Turkey, and some parts of Central Asia. Sub-Saharan Africa shows more focalized areas of risk throughout the Sahel and the Cape region.

Conclusions

These new risk maps provide a valuable starting point for understanding the zoonotic niche of CCHF, its extent, and the risk it poses to humans.