Rise in dengue fever outbreaks across the Pacific driven by the climate crisis, experts say

Dengue fever, a viral illness spread by Aedes mosquitoes, has been spreading across Pacific countries. Photograph: Majority World/Universal Images Group/Getty Images

The climate crisis is driving a sharp rise in dengue fever cases across the Pacific islands, experts say, as infections hit their highest level in a decade and several countries declare emergencies.

Pacific Island countries and territories have reported 16,502 confirmed cases and 17 deaths since the start of 2025, according to the Pacific Syndromic Surveillance System (PSSS), which collaborates with the World Health Organization (WHO) and other agencies. Infections across the region are at the highest level since 2016, the WHO said. Fiji, Samoa and Tonga are among the worst affected.