Tonga dengue outbreak update
Dengue cases have increased significantly across the Pacific islands in 2025, including in Tonga, where this mosquito-transmitted illness continues to spread.
Since the outbreak was declared on 19 February, Tonga, a country with just over 100,000 people, has recorded 864 confirmed cases and 3 dengue-related deaths. Cases have been reported on 4 main islands— confirmed cases from Tongatapu (481), Vava’u (312), ‘Eua (67) and Haápai (4).
The age group mostly affected is 10-19 years old. Youngest age affected is a 2 months old baby.
Dengue Virus Type 2 (DENV-2) is the responsible virus for this current outbreak in Tonga.
The Ministry of Health has been promptly responding to the outbreak. After 3 deaths, the Ministry conducted a national review that aimed to identify best practices, challenges, lessons learned, and to propose corrective measures in the outbreak response on 6 May, with support from WHO.
Tonga is taking decisive actions to limit the spread of the virus and protect communities across the country:
WHO deployed a clinical management expert to Tonga on 20 May. The expert worked with local health teams to enhance patient care, focusing on early identification of warning signs, effective symptom management, and quick referral of severe cases.
To combat dengue effectively, the Ministry of Health and WHO are also working together to improve the reporting and tracking of dengue cases, with an emphasis on early recognition of severe dengue warning signs.
An updated surveillance plan is now being put into action.
Controlling mosquito numbers has been another component of Tonga’s dengue response. To achieve this goal, the government reduces the breeding sites and provides treatments with larvicides. WHO has sent supplies like larvicides, insecticides, and repellents to Tonga.
The Ministry of Health, in partnership with WHO, has been sharing practical messages including on severe dengue and early warning signs widely through radio, TV, SMS, posters, and village outreach.
The Tonga Ministry of Health offers the following recommendations for the public:
Continue to clean up and destroy mosquito breeding sites around the HOME and SCHOOLS. Empty old tyres and standing water containers regularly, minimum once a week.
Wear appropriate clothing to minimize mosquito bites and use mosquito nets and repellents such as lotion and spray.
While majority of dengue cases are mild and show no symptoms, the illness can become severe. Watch out for symptoms – High Fever (40°C) accompanied by two or more of the following: headache, nausea, vomiting, body ache and rash.
Even after the fever has gone away, seek immediate medical assistance if you or someone has severe abdominal pain, persistent vomiting, bleeding gums, vomiting blood, rapid breathing, fatigue/restlessness.