Climate change expands future ranges of arbovirus vectors

Mosquitoes carrying arboviruses pose serious health threats to millions of people worldwide. The range of Aedes mosquitoes is expanding, but research has focused mainly on species Ae. aegypti and Ae. albopictus, known for their role in spreading dengue, chikungunya, and Zika viruses.

In this study, researchers from Morocco explored the global distribution under current and future climatic conditions of three understudied Aedes species (Ae. japonicus, Ae. vexans and Ae. vittatus)—all confirmed transmitters of several arboviruses.

Using mainly GBIF-mediated species occurrences, the authors modelled the current ecological niches of each species based on 19 bioclimatic variables at a 5x5 km resolution. Based on general circulation models with representative concentration pathways (RCPs) of varying emission scenarios, they projected the modelled distributions into future climatic conditions.

For Ae. japonicus, the models predicted high suitability across its native range of Japan, the Korean peninsula and southern China, as well as non-native ranges in the eastern United States and most of western Europe. Ae. vexans had a similar, but broader distribution, including high suitability in southern South America. The predicted distribution of Ae. vittatus, however, showed suitability in lower latitudes with occurrence probabilities highest in Central and South America, across Africa, India, Southeast Asia and northern Australia.

Future models predicted range changes to all three species under all RCP scenarios with broad increases observed for low and intermediate pathways and small decreases for high and worst-case pathways.

By 2050, Ae. japonicus was predicted to expand its range across much of Europe, the US, Russia and central Asia, while the range of Ae. vexans was likely to also include northern Africa and southern Australia. For Ae. vittatus, future projections included expansion in sub-Saharan Africa and the Middle East.