Worldwide niche and future potential distribution of Culicoides imicola, a major vector of bluetongue and African horse sickness viruses.
Authors: Guichard Sylvain, Guis Hélène, Tran Annelise, Garros Claire, Balenghien Thomas, Kriticos Darren J
Journal: PloS one
Summary
# Editorial Summary: Culicoides imicola Distribution and Climate-Related Disease Risk Guichard and colleagues used ecological niche modelling (CLIMEX) to map the current and projected future distribution of *Culicoides imicola*, the principal midge vector of bluetongue and African horse sickness—two economically significant diseases affecting equine and livestock populations globally. By analysing the species' response to monthly climatic variables at 10-minute spatial resolution, the researchers created detailed worldwide distribution maps and modelled potential range shifts under climate change scenarios, revealing that irrigation infrastructure substantially supports vector persistence in otherwise unsuitable arid zones. The findings indicate that *C. imicola*'s potential range in Europe extends further west than currently documented, suggesting either active range expansion or presence of non-climatic factors limiting observed distribution, whilst similar ecological niches between *C. imicola* and the Australasian *C. brevitarsis* pose important biosecurity questions for currently disease-free regions. Under future warming, the modelled niche is predicted to shift northward in the Northern Hemisphere—particularly threatening Western Europe—whilst African populations may contract, fundamentally altering the geographic risk landscape for both bluetongue and African horse sickness. Equine professionals and disease-control authorities should reassess biosecurity protocols and surveillance strategies in regions where climatic suitability for *C. imicola* is increasing, as vector-borne disease risk in previously protected areas is likely to intensify with ongoing climate change.
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Practical Takeaways
- •Monitor for Culicoides imicola in Western European regions beyond its currently documented range, as climatic conditions now support establishment and disease transmission risk is rising
- •Irrigation infrastructure in arid and semi-arid regions creates suitable habitats for the vector independent of rainfall—consider vector management around artificial water sources in endemic areas
- •Expect northward range expansion of bluetongue and African horse sickness vectors over coming decades; reassess biosecurity protocols and disease surveillance in previously low-risk northern regions
Key Findings
- •Culicoides imicola's suitable climatic niche extends further west in Europe than currently reported, suggesting ongoing colonization
- •Irrigation supports C. imicola occurrence in arid regions, expanding potential vector habitat beyond natural precipitation patterns
- •Under climate change scenarios, C. imicola distribution is projected to expand northward in the Northern Hemisphere, increasing AHS and bluetongue risk in Western Europe
- •African populations of C. imicola may contract under future climate scenarios while biosecurity risks increase globally in newly suitable regions