WHO Issues 731st Dengue Update Amidst High Burden in Western Pacific, Including Tokelau

WHO Highlights Persistent Dengue Challenge in Western Pacific

The World Health Organization (WHO) has issued its 731st situation update on dengue, drawing attention to the sustained high burden of mosquito-borne diseases throughout the Western Pacific Region. This extensive region, which encompasses numerous island nations including Tokelau, continues to grapple with the public health threat posed by dengue, a viral infection transmitted by mosquitoes. The WHO's regular updates aim to monitor the epidemiological situation, detect unusual trends, and support regional response efforts.

Regional Epidemiology and Surveillance Efforts

Dengue remains endemic in several countries within the Western Pacific Region, such as Cambodia, Lao People's Democratic Republic, the Philippines, and Viet Nam. It also poses a significant threat to Pacific Island Countries and Areas. The WHO's Western Pacific Regional Office employs both indicator-based and event-based surveillance systems to track the disease, with summaries of the situation typically published bi-weekly. Data for Pacific Island Countries are often derived from syndromic surveillance, provided by the WHO Division of Pacific Technical Support.

Rising Cases Across Pacific Island Nations

Recent reports indicate a sharp increase in mosquito-borne diseases, including dengue fever, across various Pacific Island nations. As of July 2025, the Pacific Community (SPC) highlighted a rise in cases, with countries like Samoa, American Samoa, the Cook Islands, French Polynesia, Fiji, Kiribati, Nauru, Tonga, and Tuvalu reporting confirmed cases. For instance, Samoa has recorded over 14,000 clinically diagnosed dengue cases since January 2025, alongside seven reported deaths. The circulation of multiple dengue serotypes, including DENV-1 and DENV-2, has been observed in several affected areas.

Environmental Factors and Ongoing Response

The intensification of El Niño–Southern Oscillation (ENSO) events has been linked to an increased risk of dengue outbreaks. Fluctuations in ENSO can create environmental conditions, such as altered rainfall patterns and temperatures, that are conducive to the proliferation of the Aedes aegypti mosquito, the primary vector for dengue. These conditions can expand mosquito habitats and prolong transmission seasons. The ongoing surveillance and public health advisories from organizations like the WHO are crucial in managing the persistent challenge of dengue in the Western Pacific Region, emphasizing the need for continued vigilance and preventative measures against mosquito breeding and bites.