The Pacific region is currently under close observation by health authorities as several infectious diseases show ongoing activity. From persistent dengue outbreaks to a significant measles surge and the emergence of bird flu, public health bodies are working diligently to manage these challenges and keep communities informed and safe. This report highlights the key health concerns and the ongoing efforts to address them as of late June 2026. ## Dengue Fever: A Persistent Threat Across the Pacific Dengue, a mosquito-borne illness, continues to pose a major health challenge in several Pacific island nations. The disease, transmitted by Aedes mosquitoes, typically causes flu-like symptoms but can lead to severe complications in some cases. Public health efforts across the region are focusing on mosquito control and community awareness to curb its spread. In **Kiribati**, the dengue outbreak, which began in April 2025, is still active. As of June 16, 2026, over 2,100 cases have been reported, with both DENV-1 and DENV-2 strains circulating, primarily in South Tarawa. While most cases have been mild, there has been one fatality and numerous hospitalizations. Authorities are conducting house-to-house inspections, eliminating breeding sites, and promoting health education to manage the situation. **New Caledonia** has reported more than 2,100 dengue cases since January 2026, with DENV-1 being the sole circulating serotype. Encouragingly, case numbers have been steadily decreasing. The unique approach of using Wolbachia-carrying mosquitoes, supported by the World Mosquito Program in Greater Nouméa, appears to be helping limit transmission in that area, showcasing an innovative control method. **Samoa** is also grappling with a significant dengue outbreak, reporting 150 new cases in a single week (June 8-14, 2026), marking a 17% increase. Both DENV-1 and DENV-2 are co-circulating, with the majority of cases occurring on Upolu island and disproportionately affecting children under 15. Since January 2025, Samoa has recorded nearly 20,000 clinically diagnosed cases and nine dengue-related deaths, underscoring the severity of the situation. Ongoing public health measures include community awareness campaigns, vector control, and promoting early medical attention. A new dengue outbreak has been officially declared in **Vanuatu**, specifically on South Efate Island in Shefa Province. This follows a sustained increase in cases, exceeding the alert threshold. While the specific dengue serotype is still being identified, investigations point to local transmission. One hospitalization has been reported, but no deaths. This declaration has prompted a red alert, signaling increased concern and intensified response efforts. Furthermore, travel-related dengue cases have been noted in **Hawai'i** (in a visitor from an endemic region) and **New Zealand** (in a traveler from the Cook Islands), highlighting the regional interconnectedness of disease transmission and the importance of travel advisories. ## Measles: A Resurgence Requiring Vigilance Measles, a highly contagious viral disease, continues its activity across parts of the Pacific and Asia, posing a serious threat, especially to unvaccinated populations. The disease, characterized by fever, rash, and respiratory symptoms, can lead to severe complications like pneumonia, encephalitis, and even death, particularly in young children. **Australia** has seen ongoing measles cases, often linked to international travel and subsequent local spread. New South Wales issued an alert for Sydney's CBD and surrounding areas after a confirmed case in a returning traveler. Nationally, over 100 cases have been reported in 2026, primarily affecting unvaccinated or under-vaccinated individuals. Health authorities are strongly advocating for two doses of the measles-mumps-rubella (MMR) vaccine, especially for those born after 1965 and before international travel. **Bangladesh** is experiencing one of its most severe measles outbreaks in recorded history. Since mid-March 2026, nearly 92,000 suspected and over 10,900 confirmed cases have been reported, resulting in 677 deaths, mostly among children. The overwhelming number of hospitalizations has strained health services, and the outbreak has not yet peaked. The primary drivers are identified as gaps in immunization coverage, exacerbated by a vaccine shortage in 2024-2025 and the absence of supplementary vaccination campaigns since 2020. A nationwide measles-rubella campaign launched in April 2026, though with high reported coverage, began after the outbreak was already well underway. Despite achieving measles elimination status in 2015, **Japan** has also seen a resurgence in 2026, with 525 cases reported as of early June. While weekly case counts have started to decline, this is the highest number for this period since 2019. Tokyo accounts for the largest share of cases, with both domestic transmission and imported infections. A significant proportion of cases are among adults aged 20-39 who are unvaccinated or incompletely vaccinated. Japanese health authorities are urging the public and healthcare providers to verify vaccination status and ensure full two-dose coverage. ## Whooping Cough (Pertussis) in New Zealand **New Zealand** continues to battle an ongoing national epidemic of pertussis, commonly known as whooping cough. This highly contagious bacterial infection primarily affects the respiratory system, causing severe coughing fits that can make breathing difficult, particularly in infants. As of mid-June 2026, weekly case numbers increased to 31, contributing to a cumulative total of 885 cases for the year. Notification rates remain highest among young children aged 1-4 years and infants under one year, who are most vulnerable to severe outcomes. Vaccination is crucial for preventing pertussis, with childhood immunizations and booster shots for pregnant individuals being key strategies to protect both infants and the broader community. ## Rotavirus: Tackling Diarrhea in Kiribati In **Kiribati**, a rotavirus outbreak, which causes severe diarrhea, remains ongoing, although surveillance data indicates a declining trend after peaking earlier in the year. A cumulative total of 6,525 diarrhea cases have been reported nationwide. Transmission continues to be concentrated in South Tarawa, especially in Betio, with children under five years old being the most affected group. The cumulative death toll stands at three confirmed deaths, with two more under investigation. Health interventions include enhanced surveillance, laboratory testing, contact tracing, and health promotion focusing on child health and hygiene to prevent further spread. Rotavirus vaccination is a highly effective way to protect children from this common and potentially serious illness. ## Avian Influenza (Bird Flu) H5N1 Arrives in Australia A significant development is the first-ever detection of highly pathogenic avian influenza (HPAI) H5 in Australia. On June 20, 2026, the CSIRO Australian Centre for Disease Preparedness confirmed HPAI H5N1 clade 2.3.4.4b in a sick brown skua, a migratory seabird, found in Cape Le Grand National Park, Western Australia. Another seabird from the same area also showed a suspect-positive result. While H5N1 has devastated wildlife globally, its arrival in Australia was believed to be delayed, likely introduced by marine birds from the Southern Ocean. Experts suggest it may not widely establish on the mainland unless transmitted to freshwater ducks. Crucially, there have been no detections in poultry, and no mass mortality in other species has been observed. Australian health authorities, including the Australian Centre for Disease Control and WA Health, assess the public health risk to humans as low, emphasizing that transmission requires close contact with infected animals, and human-to-human spread is exceedingly rare. Food Standards Australia New Zealand has also confirmed no food safety risk from properly handled and cooked poultry products. A small number of individuals who had direct contact with the affected birds are being monitored, but there is no risk to the broader community. The public is strongly advised not to touch or handle sick or dead birds, and poultry owners are urged to follow biosecurity guidelines and report suspicious flock mortality immediately. The WA Chief Health Officer also recommends receiving the seasonal influenza vaccine to reduce the risk of co-infection, which could potentially lead to the emergence of new influenza strains. These ongoing health alerts across the Pacific underscore the dynamic nature of infectious diseases and the continuous need for robust surveillance, rapid response, and community engagement to protect public health.