Countries across the Oceania region are diligently tracking and responding to several significant health challenges, as outlined in recent reports. From mosquito-borne illnesses like dengue fever to highly contagious vaccine-preventable diseases such as whooping cough and measles, public health agencies are on high alert. These ongoing situations highlight the critical importance of robust surveillance, effective vaccination programs, and community-level preventative actions. Additionally, international travel continues to play a role in disease spread, necessitating coordinated global efforts. ## Dengue Fever: A Persistent Threat Across the Pacific Dengue fever, a viral infection transmitted by *Aedes* mosquitoes, remains a significant public health concern in tropical and subtropical regions, including many Pacific islands. Symptoms can range from mild fever and body aches to severe, potentially life-threatening conditions like dengue hemorrhagic fever. Preventing mosquito bites and eliminating breeding sites are crucial for control. In **New Caledonia**, the circulation of dengue, predominantly DENV-1 serotype, continues to be a major challenge. As of early May 2026, over 1,500 cases have been reported since January, indicating sustained transmission. Environmental factors like heavy rainfall and standing water provide ideal breeding grounds for mosquitoes, while travel between communities can aid viral spread. Health authorities are actively encouraging residents to seek prompt medical attention for symptoms and to intensify mosquito control efforts around their homes and workplaces. **Samoa** is also grappling with ongoing dengue transmission, reporting 153 new cases in a recent epidemiological week, though this marks a slight decrease from the previous period. Both DENV-1 and DENV-2 serotypes are circulating, with a disproportionate number of cases affecting children under 15. The disease is widespread across Upolu and Savai’i islands. Since January 2025, the nation has recorded thousands of clinically diagnosed cases and several associated deaths, underscoring the severe impact of this disease. Meanwhile, **Tonga** has declared a dengue outbreak in April 2026, with DENV-2 identified as the circulating serotype. Most cases are concentrated in Tongatapu, predominantly affecting children and adolescents. The detection of imported dengue cases in **New Zealand**, linked to travelers returning from Samoa, serves as a reminder of how quickly diseases can cross borders, emphasizing the need for regional vigilance. ## Whooping Cough (Pertussis): Protecting Our Youngest Whooping cough, or pertussis, is a highly contagious respiratory infection caused by bacteria. It’s particularly dangerous for infants and young children, often leading to severe coughing fits, difficulty breathing, and even death. Vaccination through the DTaP vaccine is the most effective way to prevent this illness. **Guam** is experiencing continued circulation of pertussis, with 24 cases identified since late 2025 and 15 in 2026 alone. Cases span all age groups, from infants to adults, with many individuals either unvaccinated or only partially vaccinated. Public health actions include thorough contact tracing, offering preventive medication to close contacts, and a strong push to improve DTaP vaccination rates, especially for pregnant women and vulnerable infants. These measures are vital to protect those most at risk. **New Zealand** continues to face a significant pertussis epidemic that began in October 2024, with hundreds of cases reported in 2026. Although weekly case numbers have seen some reduction since the year's start, transmission remains active. The illness has led to numerous hospitalizations and at least one death, highlighting its serious nature. Infants under one year old remain the most vulnerable group, reinforcing the urgent need for timely vaccination. In **Vanuatu**, while pertussis transmission appears to be slowing from its peak in late 2025, the number of cases still exceeds epidemic thresholds. The disease has resulted in several deaths, primarily on Tanna and Shefa. Children aged one to nine years, alongside infants, show the highest incidence, and a significant proportion of recorded cases are among unvaccinated or partially vaccinated individuals. Enhanced surveillance and catch-up vaccination campaigns are ongoing to bolster community immunity and reduce further spread. ## Measles: The Importance of Immunization Measles is an extremely contagious viral disease that can lead to severe complications, including pneumonia, encephalitis, and even death, especially in young children and immunocompromised individuals. It spreads through airborne droplets and is preventable with two doses of the Measles, Mumps, and Rubella (MMR) vaccine. **Australia** is actively managing ongoing measles circulation, with most cases linked to international travel and subsequent local transmission. Early May 2026 saw cases reported predominantly in New South Wales and Victoria, often originating from travel to Southeast Asia. Public health authorities in Sydney and Sutherland Shire have issued alerts for potential exposure sites, including healthcare facilities and public venues, prompting contact tracing and health monitoring. Nationally, surveillance data consistently indicates that many affected individuals are either unvaccinated or have an unknown vaccination status. **New Zealand** has also reported new measles cases in Wellington, including an autochthonous case (meaning it originated locally rather than from international travel) with no clear link to previous cases. This suggests local community transmission may be occurring. Authorities are intensely investigating these links, tracing contacts, and advising the public to verify their MMR vaccination status. Free MMR vaccination is being offered in affected areas for those over 12 months of age to quickly boost protection. The global context further highlights the measles threat. **Bangladesh** is experiencing a severe national resurgence, with tens of thousands of suspected cases and hundreds of suspected deaths since mid-March 2026, overwhelming health services. This massive outbreak, driven by vaccination gaps, has prompted an emergency vaccination campaign. Similarly, **Japan**, despite its measles elimination status since 2015, has seen a rising trend of cases in multiple prefectures, a mix of imported and local transmissions, largely among unvaccinated individuals. These situations globally underscore the fragility of immunity when vaccination rates decline and the ease with which measles can spread through international travel. ## Rotavirus and Diarrheal Diseases: Hygiene is Key Rotavirus is a common cause of severe diarrhea in infants and young children, leading to dehydration and, in some cases, death. It spreads easily through the fecal-oral route. Safe water, sanitation, hygiene, and vaccination are crucial for prevention. In **Kiribati**, a rotavirus epidemic continues, though it shows signs of gradually slowing. Thousands of diarrhea cases have been reported across the country, with transmission heavily concentrated in South Tarawa, particularly Betio. Children under five years old remain the most affected demographic, and the epidemic has tragically resulted in several confirmed and suspected deaths. Public health efforts are focused on enhanced surveillance, laboratory confirmation, and aggressive promotion of health and hygiene practices within communities, with a particular emphasis on child health. Meanwhile, the **Federated States of Micronesia**, specifically Chuuk State, continues to manage diarrheal diseases in the aftermath of Typhoon Sinlaku. Concerns persist due to environmental factors and ongoing water safety challenges. A single laboratory-confirmed cholera case was identified, triggering immediate investigations into potential water sources. While the identified strain was not considered to have epidemic potential, this incident underlines the vulnerability of communities to waterborne illnesses, especially following natural disasters. Efforts to improve water, sanitation, and hygiene (WASH) infrastructure and practices are being intensified in affected areas. ## Hantavirus Alert: A Cruise Ship Connection Hantavirus is a serious viral disease primarily transmitted to humans through contact with rodents or their droppings and urine. However, the Andes virus serotype, identified in a recent international incident, is one of the rare hantaviruses that can also spread from person to person, though typically with low efficiency. Symptoms can include fever, muscle aches, and severe respiratory distress. An international alert was issued following a cluster of hantavirus cases, caused by the Andes virus, linked to passengers and crew aboard the MV Hondius cruise ship. As of early May 2026, eight cases and three deaths have been associated with this outbreak. The international nature of cruise travel meant that disembarked passengers could potentially carry the virus to various countries. Public health authorities responded swiftly across several nations. In **Singapore**, two exposed residents tested negative for the virus and the overall public health risk was deemed low. **French Polynesia** tracked a contact who transited through Tahiti and Mangareva; this individual, though asymptomatic, was quarantined to prevent further potential spread. **Australia** repatriated several of its citizens and a New Zealander from the ship, placing them under protective quarantine in Western Australia, despite all being asymptomatic. The World Health Organization continues to assess the overall public health risk as low but stresses the critical importance of rapid case detection, isolation of suspected cases, and international contact tracing, particularly given the long incubation period of hantavirus, even with its low human-to-human transmission potential. ## Collective Action for Public Health The ongoing health alerts in Oceania and beyond underscore the interconnectedness of global health. The sustained outbreaks of dengue, whooping cough, measles, and rotavirus, alongside the international hantavirus incident, call for a unified and proactive approach. Key actions include strengthening disease surveillance systems to detect and respond to outbreaks rapidly, increasing vaccination coverage to prevent the spread of vaccine-preventable diseases, promoting stringent hygiene and sanitation practices, and implementing effective vector control measures. Community engagement is paramount, as individual actions, such as seeking early medical care, adhering to public health advice, and maintaining personal hygiene, collectively contribute to broader public health outcomes. International collaboration and information sharing between countries and global health organizations are also indispensable in monitoring and containing cross-border health threats. By working together, communities and health authorities can better protect populations from these evolving health challenges and build a more resilient public health landscape for the future.