In April this year, the small Pacific island country of Samoa declared a dengue outbreak, reflecting a concerning trend of escalating rates of dengue cases across the World Health Organization (WHO) Western Pacific Region. The Region’s Pacific island countries and areas are particularly vulnerable to dengue outbreaks due to favourable mosquito breeding conditions and different circulating strains of the virus. Given the risk of dengue spreading to other countries, WHO is implementing priority public health interventions in partnership with ministries of health across the Region to curb transmission and save lives.
Successful dengue control efforts rely on sound monitoring and surveillance. WHO is working with ministries of health to monitor dengue surveillance data and predict future trends. Beyond surveillance, the Organization is also responding to dengue outbreaks by mobilizing logistics and supplies for vector control, providing technical support for early detection and clinical management, and reducing risk through risk communication and community engagement at the country level.
Mobilizing logistics and supplies for vector control
WHO promotes vector control measures to reduce dengue transmission, thereby decreasing the incidence of infection and preventing outbreaks. After Samoa declared the dengue outbreak following an increase in cases since November 2023, the island nation intensified vector control efforts to reduce the spread of the disease. This included prioritizing fumigation around schools and medical facilities in areas with higher numbers of reported cases. WHO supported these efforts by providing vector control supplies, including disinfectant sprayers, protective goggles, face shields and foggers.
Community vector control activities in Samoa (Photo credit: Ministry of Health Samoa)
Providing technical support for early detection and clinical management
In Western Pacific countries where dengue is endemic, clinical management capacity has been strained by large-scale, prolonged and ongoing outbreaks, especially after the COVID-19 pandemic. The influx of dengue patients to health-care facilities during outbreaks stresses health-care systems, affecting the quality of care and health outcomes.
To address these challenges, WHO is working with health authorities across affected countries to implement guidelines on dengue clinical management, update clinical management protocols and leverage tools to assess the risk of severe dengue disease. Early detection and timely diagnosis are crucial for effective clinical management of dengue. To support early diagnosis, WHO provided Samoa and the Philippines with rapid dengue diagnostic tests, prioritizing high-burden areas.
In addition, WHO plans to build clinical management capacities among clinicians working at all levels from primary to tertiary care, as well as among health-care and hospital administrators. This capacity-building will include diagnosing and managing patients with severe cases, ensuring timely referral and improving case management.
Reducing risk through risk communication and community engagement
Communities are pivotal to the success and sustainability of vector control measures. In addition to risk communication, WHO promotes community engagement, encouraging communities to take responsibility for and to implement these measures.
In Samoa, a community-led half-day clean-up campaign brought together members of the public to eliminate potential mosquito breeding areas in their neighbourhoods. The Government also engaged the media to promote preventative measures to the population, such as eliminating stagnant water sources, identifying the signs and symptoms of dengue and using mosquito nets and repellents. Dr Kim Eva Dickson, WHO Representative for Samoa, noted: “Samoa has really ramped up its efforts to combat dengue and improve overall mosquito control efforts. We are happy to support and will continue to work with the Ministry of Health on its elimination measures as well as public education and awareness.”
Community engagment for vector control in Samoa (Photo credit: Ministry of Finance, Government of Samoa)
Risk communication plays a fundamental role in preventing and controlling disease outbreaks. For example, the Philippines is leveraging risk communication to promote a public health measure. The “4 o’clock habit,” or the practice of cleaning one’s surrounding environment at four o’clock in the afternoon, is widely promoted. WHO is supporting the Philippine Department of Health to implement a mixed-methods study to evaluate the effectiveness of existing risk communication messages. Insights from the study will inform dengue prevention and control communication campaigns that will be rolled out to communities ahead of the rainy season.
Risk communication activities in the Philippines (Photo credit: WHO Philippines)
Through surveillance, technical assistance, provision of essential supplies, risk communication and community engagement, WHO is actively responding to dengue outbreaks and reducing dengue transmission across the Region. According to Tagaloa Dr Robert Thomsen, Acting Director General and Deputy Director of Health, Public Health, from the Ministry of Health in Samoa, “WHO’s continued technical assistance and provision of essential supplies, such as the 1250 rapid diagnostic testing kits and spraying equipment recently received, provide important support to Samoa’s dengue control activities. We continue to strengthen surveillance and public and community awareness prevention and control activities. This multi-pronged approach has helped to contain the outbreak.”