The overlapping global distribution of dengue, chikungunya, Zika and yellow fever
Ahyoung Lim, Freya M. Shearer, Kara Sewalk, David M. Pigott, Joseph Clarke, Azhar Ghouse, Ciara Judge, Hyolim Kang, Jane P. Messina, Moritz U. G. Kraemer, Katy A. M. Gaythorpe, William Marciel de Souza, Elaine O. Nsoesie, Michael Celone, Nuno R. Faria, Sadie J. Ryan, Ingrid B. Rabe, Diana P. Rojas, Simon I Hay, John S. Brownstein, Nick Golding, Oliver J. Brady
Abstract
Arboviruses transmitted mainly by Aedes (Stegomyia) aegypti and Ae. albopictus, including dengue, chikungunya, and Zika viruses, and yellow fever virus in urban settings, pose an escalating global threat. Existing risk maps, often hampered by surveillance biases, may underestimate or misrepresent the true distribution of these diseases and do not incorporate epidemiological similarities despite shared vector species. We address this by generating new global environmental suitability maps for Aedes-borne arboviruses using a multi-disease ecological niche model with a nested surveillance model fit to a dataset of over 21,000 occurrence points. This reveals a convergence in suitability around a common global distribution with recent spread of chikungunya and Zika closely aligning with areas suitable for dengue. We estimate that 5.66 (95% confidence interval 5.64-5.68) billion people live in areas suitable for dengue, chikungunya and Zika and 1.54 (1.53-1.54) billion people for yellow fever. We find large national and subnational differences in surveillance capabilities with higher income more accessible areas more likely to detect, diagnose and report viral diseases, which may have led to overestimation of risk in the United States and Europe. When combined with estimates of uncertainty, these suitability maps can be used by ministries of health to target limited surveillance and intervention resources in new strategies against these emerging threats.