Across the vast and diverse Pacific region, health authorities are diligently monitoring and responding to a range of infectious disease threats. The latest reports highlight ongoing efforts to curb outbreaks of dengue fever, address a significant measles situation, and manage persistent pertussis cases, alongside watchful surveillance for other emerging concerns like avian influenza. These health updates underscore the critical importance of robust public health systems, community engagement, and regional collaboration to protect populations. ## Dengue Fever: A Persistent Threat in the Pacific Dengue fever, a mosquito-borne illness, continues to pose a significant health challenge across several Pacific island nations. This viral infection, spread by Aedes mosquitoes, can cause severe flu-like symptoms, and in some cases, life-threatening complications. Effective prevention relies heavily on controlling mosquito populations and protecting oneself from bites. In **New Caledonia**, the dengue epidemic appears to be on a downward trend, with 2,221 cumulative cases reported since the start of 2026. Only seven new cases were noted in the most recent update, suggesting a decline consistent with the cooler season, which naturally slows mosquito activity. The circulating strain remains Dengue Serotype 1 (DENV-1), and a 'blue alert' is maintained, indicating a need for continued vigilance despite the decreasing case numbers. However, the situation is more concerning in **Vanuatu**, particularly on South-West Efate Island in Shefa Province, where a dengue outbreak persists. With 48 laboratory-confirmed cases, including two new ones in a recent week (EpiWeek 29, referring to the 29th epidemiological week of the year), there is clear evidence of ongoing local transmission. Nearly 19% of patients have required hospitalisation, and cases are geographically widespread, affecting areas like Pango, Erakor, Port Vila, and Mele. Investigations reveal a mix of local transmission and potential imported cases from travel to Fiji. All confirmed samples were DENV-1, prompting a 'red alert' to signify an active and significant outbreak requiring intensive public health intervention. Similarly, **Wallis and Futuna** is grappling with a progressing dengue epidemic, logging 50 confirmed and probable cases since January 2026, split between Futuna and Wallis. The past week saw three new confirmed cases, and an increase in dengue-like symptoms has been observed, particularly in Futuna. With 8% of cases requiring hospital care, authorities are urging strengthened community-level mosquito control measures as a 'red alert' remains in effect for DENV-1. ## Measles Outbreak Declared in Papua New Guinea Measles, a highly contagious viral disease, has been officially declared an outbreak in **Papua New Guinea (PNG)**. This declaration came after laboratory confirmation of cases in New Ireland and East Sepik provinces. The first confirmed case was an 18-month-old girl in New Ireland Province, followed by two adult males in East Sepik. Worryingly, no direct epidemiological link has been established between these initial cases, suggesting separate introductions or undetected spread. Furthermore, a 'borderline' result in Madang Province is under investigation, hinting at a potentially broader reach. Since January 2026, PNG has reported 108 suspected measles and rubella cases, with serum samples collected from eight provinces. While three have been confirmed for measles, 77 tested negative for both, and 29 are still awaiting results. A critical challenge is the exhaustion of serology reagents at the Port Moresby laboratory, necessitating the urgent transfer of samples to the Victorian Infectious Diseases Reference Laboratory in Australia for testing. In response, rapid response teams have been deployed, initiating outbreak immunisation campaigns in affected communities like Kairiru Island, East Sepik, and in New Ireland Province. These efforts, supported by the WHO, include contact tracing, active case finding, clinician training, and public awareness campaigns. A 'red alert' for measles has been added, emphasizing the severity and need for urgent action to prevent wider transmission of this vaccine-preventable disease. ## Pertussis (Whooping Cough) Continues in New Zealand **New Zealand** is experiencing an ongoing national epidemic of pertussis, commonly known as whooping cough, which was initially declared in November 2024. This highly contagious respiratory infection, characterized by severe coughing fits, poses a particular risk to infants and young children who are not yet fully vaccinated. The surveillance week ending July 17, 2026, saw 25 new cases, a slight increase from the previous week, bringing the cumulative total for 2026 to 1,062 cases. A 'blue alert' remains in place, signifying that while the situation is being managed, public health vigilance and continued vaccination efforts are essential to control the spread of this preventable disease. ## Avian Influenza Surveillance in Australia and Regional Implications **Australia** is actively monitoring detections of Highly Pathogenic Avian Influenza (HPAI), specifically the H5N1 clade 2.3.4.4b, in wild seabirds. As of July 26, 2026, a total of 20 detections have been confirmed across four states: Western Australia, South Australia, New South Wales, and Queensland. The virus, part of a globally circulating strain, was recently found in Queensland in a dead petrel, triggering emergency biosecurity measures and enhanced surveillance. Two additional detections in South Australia involved resident native species, unlike earlier cases in migratory birds, prompting further analysis to determine if this signifies local transmission or new introductions. Crucially, there have been no detections in poultry or commercial farms, and no evidence of mass mortality among wild birds. The risk to human health from these detections remains low. However, these ongoing findings serve as a vital reminder of the potential for H5N1 to enter the Pacific region via migratory bird pathways, reinforcing the need for continuous vigilance and strengthened surveillance across all Pacific nations. ## Broader Respiratory Disease Concerns in Palau In **Palau**, the Ministry of Health and Human Services is responding to an increase in respiratory illnesses, particularly COVID-19. As of July 24, 2026, 85 COVID-19 cases and nine hospital admissions were reported, marking an increase from previous figures. Alongside this, Palau continues to manage cases of tuberculosis (TB) and pertussis, with ongoing case investigations, contact tracing, and follow-up activities. These integrated efforts are crucial for minimizing transmission within the community and protecting vulnerable individuals from a range of respiratory pathogens. ## The Importance of Vigilance and Collaboration These diverse health alerts across the Pacific highlight the interconnectedness of public health and the constant need for readiness. From vector-borne diseases like dengue and zika (with New Zealand reporting imported cases), to vaccine-preventable diseases like measles and pertussis, and emerging zoonotic threats such as avian influenza, each situation demands a coordinated response. Strong surveillance systems, timely laboratory testing, effective public health interventions like vaccination and vector control, and clear communication with communities are foundational. Regional bodies like the Pacific Public Health Surveillance Network (PPHSN) play a vital role in sharing information and coordinating responses, ensuring that the Pacific remains resilient in the face of evolving health challenges. Community participation in preventive measures, understanding symptoms, and seeking early medical attention are equally crucial in preventing the wider spread of these diseases. Ultimately, the ongoing efforts across New Caledonia, Vanuatu, Wallis and Futuna, Papua New Guinea, New Zealand, Australia, and Palau underscore a collective commitment to health security in the Pacific. By remaining vigilant, collaborating regionally, and empowering communities with knowledge, the region can better navigate these health landscapes.