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

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, The Guardian reported.

Pacific Island countries and territories have reported 16,502 confirmed cases and 17 deaths since the start of 2025, The Guardian reported citing 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.

Dr Paula Vivili, deputy director general of the Pacific Community (SPC), said historically dengue outbreaks were seasonal.

“However, due to climate change, transmission seasons are lengthening, and some areas are experiencing year-round dengue risk,” Vivili said, according to The Guardian.

Dengue fever, a viral illness spread by Aedes mosquitoes, causes high fever, severe headache, joint and muscle pain, rash, and in severe cases can be fatal. Rising temperatures, rainfall and increased humidity are creating ideal breeding conditions for Aedes mosquitoes, even in areas previously unsuitable for transmission.