The patterns and drivers of Oropouche virus and its primary vector invasions in Asia under global change.

BACKGROUND

The 2024 Oropouche fever outbreak marks a major public health event, with documented fatalities and confirmed cases of vertical transmission. Given increasing global connectivity and environmental change, there is potential for the spread of Oropouche fever from its currently endemic regions into other regions like Asia. To prevent the spread of the disease, it is important to understand the potential ecological niche of Oropouche virus (OROV) and its primary vector, Culicoides paraensis, and to identify the major environmental drivers.

METHODS

Georeferenced occurrence records of C. paraensis and OROV were compiled together with climate, land use, elevation and population datasets. Both current conditions and future climate projections derived from the Coupled Model Intercomparison Project Phase 6 under different Shared Socioeconomic Pathway scenarios were incorporated. Random forest models were used to predict the potential ecological niches of C. paraensis and OROV, and structural equation modeling was applied to evaluate relationships among vector suitability, virus suitability, and environmental drivers.

RESULTS

Currently, C. paraensis suitability was concentrated in Southeast Asia, southern China, the Korean Peninsula, Japan, Sri Lanka, and parts of India, while OROV exhibited an overlapping but lower suitability. Under future scenarios, C. paraensis niches were projected to shrink, whereas areas with potential environmental suitability for OROV expanded except under SSP5-8.5, an extreme fossil fuel-driven scenario with very high radiative forcing. Precipitation and land cover primarily drive C. paraensis, while OROV was influenced by temperature, precipitation, and land cover.

CONCLUSIONS

Global change may lead to the invasion of C. paraensis and OROV into new areas of Asia if the virus and its vector are introduced. These findings support integrated, nature-based strategies for Oropouche fever surveillance, mitigation, and prevention.