The Pacific region and its surrounding areas are currently facing a complex array of public health challenges, with various infectious diseases under active surveillance by health organizations. From ongoing dengue fever outbreaks to persistent measles activity, the alerts highlight the continuous need for vigilance, robust public health infrastructure, and community engagement to safeguard population health. This update compiles the latest information, emphasizing both the current status of these health concerns and the ongoing efforts to manage them as of March 24, 2026. ## Understanding Dengue Fever in the Pacific Dengue fever, a mosquito-borne illness, continues to be a significant public health concern across several Pacific nations. This viral infection can range from mild flu-like symptoms to severe, potentially life-threatening forms. Prevention largely hinges on effective mosquito control and personal protection. **New Caledonia** is experiencing sustained local dengue transmission, with a steady increase in cases. As of March 19, 2026, 340 individuals had been reported with dengue since the beginning of the year, a rise from 268 cases just five days prior. The DENV-1 serotype remains dominant, and the disease is circulating in multiple municipalities, particularly in the northern and eastern parts of the territory. This ongoing activity maintains a blue alert for DENV-1, signifying continuous monitoring and response efforts. Meanwhile, **Samoa** is grappling with a prolonged dengue outbreak. Since January 1, 2025, a staggering 17,577 cases have been clinically diagnosed, with 5,170 confirmed by laboratory tests. While a slight decrease in new weekly cases was noted (170 in EpiWeek 11, down 12% from the previous week), the situation remains serious. DENV-1 accounts for 68% of confirmed cases, with DENV-2 making up the remainder. Transmission is widespread across both Upolu and Savaii islands, disproportionately affecting children under 15, who represent 74% of all cases. Nine dengue-related deaths have been recorded cumulatively. A blue alert is in effect for both DENV-1 and DENV-2, indicating persistent disease activity requiring close attention. **New Zealand** has also reported imported dengue cases, underscoring the interconnectedness of global health. During EpiWeek 11 (March 14–20, 2026), eight confirmed cases were identified in travelers returning from other regions. The majority (57%) had visited the Cook Islands, 29% from Samoa, and 14% from Indonesia. Health authorities are diligently investigating these cases, noting that some may later be reclassified due to cross-reactivity with other flaviviruses. This highlights the importance of surveillance at points of entry and advising travelers on prevention measures. ## Monitoring Measles Activity Measles, a highly contagious viral disease preventable by vaccination, poses a continuous threat, particularly in regions with suboptimal immunization rates. Its spread can be rapid and severe, especially among unvaccinated populations. **Australia** is experiencing ongoing measles activity in early 2026, primarily due to imported cases but with increasing evidence of local transmission. New South Wales (NSW) alone has confirmed 33 cases since January 1, including several locally acquired infections with no clear source, indicating community spread across Sydney's western, northern, and metropolitan areas, as well as the Nepean Blue Mountains region. Other states like Victoria, Queensland, and Western Australia have also reported sporadic cases, though numbers remain low in other territories. Public health authorities are rigorously implementing strategies such as early detection, isolation, contact tracing, and vaccination promotion to curb further spread. A red alert is in effect for measles in Australia, signaling a high level of concern and urgent response. In **Hawaiʻi**, heightened measles surveillance is underway following the detection of measles virus in wastewater from East Kauaʻi County on February 25, 2026. This environmental finding comes amidst the confirmation of one measles case on March 7, 2026, in a visitor from the continental United States who had traveled through Oʻahu and Hawaiʻi Island. Importantly, there is no epidemiological link between the wastewater detection and the confirmed case. While no community transmission has been confirmed locally, the Department of Health has alerted healthcare providers statewide and stepped up monitoring, including wastewater surveillance. This proactive approach, coupled with strong public health messaging on early identification, isolation, and vaccination, is crucial given ongoing measles activity in other parts of the U.S. ## Confronting Whooping Cough (Pertussis) Pertussis, commonly known as whooping cough, is a highly contagious respiratory infection that can be severe, particularly for infants. Vaccination is the most effective way to prevent this illness and protect vulnerable populations. **New Zealand** continues to battle an ongoing national pertussis epidemic. While recent weekly notifications have shown a decline, with 27 cases reported in the week ending March 13, 2026 (down from 40 the previous week), the cumulative total for 2026 has reached 473. Since the epidemic began in October 2024, 4,205 cases have been reported, leading to 392 hospitalizations and one fatality. Infants under one year old remain the most affected group, prompting continued emphasis on vaccination, surveillance, and protecting high-risk individuals. A blue alert for pertussis remains in effect. **Vanuatu** is also closely monitoring a pertussis outbreak that began in August 2025. While new case reports have declined, and the overall trend shows a decrease from the peak in late 2025, the outbreak is still active. The cumulative total stands at 807 cases, with 67 hospitalizations and seven pertussis-associated deaths. The highest burden is observed among children aged 1–9 years and infants. Alarmingly, 47% of cases with known vaccination status were unvaccinated. Transmission is concentrated in Efate and Tanna, with smaller clusters elsewhere. A blue alert remains in effect, indicating continued vigilance. In **Guam**, pertussis activity has also been reported, with six laboratory-confirmed cases in 2026 following the confirmation of two additional cases on March 18, 2026. These new cases were linked through direct contact. Public health authorities are conducting thorough investigations, contact tracing, and monitoring respiratory illness trends while reinforcing the critical importance of vaccination to prevent further spread. ## Addressing Rotavirus Outbreak in Kiribati Rotavirus is a common cause of severe diarrheal disease, particularly in young children, leading to dehydration and, in some cases, fatalities. Vaccination and improved sanitation are key preventive measures. **Kiribati** is managing a substantial rotavirus outbreak, with 4,854 cumulative cases reported as of March 18, 2026. While epidemiological trends suggest a decline in transmission since mid-March, following a peak in late February to early March, the situation remains serious. South Tarawa, especially Betio, continues to bear the highest case burden, although cases are also seen in North Tarawa and outer islands. Children under five years old are most affected, with 56 hospitalizations and one confirmed death, alongside four suspected deaths under investigation. Health authorities are implementing enhanced surveillance, laboratory confirmation, health promotion, and community-level hygiene interventions, while closely monitoring for any resurgence. A red alert for Rotavirus signifies a critical situation requiring sustained, high-level response. ## Other Health Concerns Across the Region Beyond these major alerts, several other health issues are being monitored: **Ciguatera Fish Poisoning in Vanuatu:** This foodborne illness, caused by consuming reef fish contaminated with ciguatoxins, remains an ongoing concern. Two new cases were reported in EpiWeek 11, bringing the cumulative total to 63 cases, with no deaths. Cases have shown a slight decline, staying below the alert threshold. Most affected individuals are males aged 15–34, linked to various fish types, with Efate accounting for the majority of cases. Surveillance continues to monitor the situation. **Gastroenteritis in Palau:** Authorities are closely watching an increase in acute gastroenteritis cases, primarily affecting adolescents aged 10–19, with clusters in Koror State. Norovirus is suspected as the cause, and investigations are ongoing. The Ministry of Health and Human Services has initiated public awareness campaigns and strengthened surveillance. **Leptospirosis in American Samoa:** An increase in leptospirosis, a bacterial disease often spread through contaminated water or soil, has led to an official outbreak declaration. Six confirmed cases since January 2026, five in March alone, include two intensive care admissions and one fatality. Health authorities emphasize early diagnosis and antibiotic treatment, along with public risk-reduction measures, especially after heavy rainfall and flooding. **Meningococcal Disease in French Polynesia and the UK:** French Polynesia confirmed its second case of invasive meningococcal disease in 2026, involving an adult who is now improving in hospital. Close contacts received preventive antibiotics. Separately, the UK Health Security Agency is investigating an outbreak in Kent, with 20 confirmed cases and two deaths reported by March 22, 2026. This outbreak primarily affects young adults and has triggered a targeted vaccination campaign. ## Collective Action for Regional Health Security The diverse nature of these alerts underscores the critical role of regional public health surveillance networks, such as the Pacific Public Health Surveillance Network (PPHSN), in sharing information and coordinating responses. Effective outbreak management relies on timely reporting, accurate diagnostics, robust vaccination programs where applicable, and widespread public awareness. For individuals, practicing good hygiene, staying up-to-date with recommended vaccinations, and seeking medical attention for concerning symptoms are vital steps. For communities, collective action in mosquito control, safe food handling, and sanitation plays an indispensable part in preventing the spread of disease. These ongoing health challenges reinforce the importance of sustained investment in public health systems and international cooperation to protect the well-being of populations across the Pacific and beyond.