Risk of yellow fever virus transmission in the Asia-Pacific region

Historically endemic to Sub-Saharan Africa and South America, yellow fever is absent from the Asia-Pacific region. Yellow fever virus (YFV) is mainly transmitted by anthropophilic Aedes mosquitoes whose distribution spans large tropical and subtropical regions. Increasing exchanges between Africa and Asia have caused imported YFV incidents in non-endemic areas, threatening Asia with a new viral emergence. Using experimental infections of field-collected mosquitoes, we show that Asia-Pacific Aedes mosquitoes are competent vectors for YFV. Aedes aegypti populations from Singapore, Taiwan, Thailand, and New Caledonia transmitted YFV 14 days after oral infection, with up to 23,000 viral particles excreted in saliva. These findings provide a comprehensive assessment showing that Ae. aegypti from the Asia-Pacific region are highly competent to YFV, indicating that vector populations are unlikely to impede YF emergence in the region.