The vast and diverse Pacific region is currently navigating a series of public health challenges, with several infectious diseases requiring active monitoring and response. From mosquito-borne illnesses like dengue fever to highly contagious respiratory diseases such such as pertussis and measles, health authorities are working tirelessly to contain transmission and protect communities. These ongoing alerts underscore the importance of early detection, strong public health interventions, and individual preventative actions, especially considering the interconnectedness of global travel and trade. ## Dengue Fever: A Persistent Threat Across the Pacific Dengue fever, a viral infection transmitted by Aedes mosquitoes, continues to be a significant public health concern across many Pacific island nations. Symptoms typically include high fever, severe headache, pain behind the eyes, muscle and joint pains, and a skin rash. While most cases are mild, severe dengue can lead to bleeding, organ damage, and can be life-threatening. Preventing dengue relies heavily on controlling mosquito populations by eliminating breeding sites – typically standing water – and protecting oneself from bites through repellents and protective clothing. **New Caledonia** is experiencing sustained dengue transmission, with over 1,500 cases reported since January 2026. The DENV-1 strain is primarily circulating, and local health authorities are urging residents to seek early medical advice for symptoms and intensify mosquito control efforts. The presence of seasonal rainfall and population movement further fuels transmission, maintaining a 'red alert' level, signifying ongoing high-level concern. In **Samoa**, dengue transmission also persists, although the latest weekly reports show a slight decrease in new cases. Both DENV-1 and DENV-2 serotypes are co-circulating, affecting both Upolu and Savai'i islands, with children under 15 years old being the most impacted. While the situation indicates 'blue alert' status, meaning ongoing but potentially stabilizing transmission, the cumulative case count since early 2025 is substantial, highlighting a long-term challenge. **Tonga** also continues to battle a dengue outbreak, predominantly caused by the DENV-2 serotype, particularly affecting children aged 11–14 in Tongatapu. While no hospitalizations or deaths have been reported recently, the 'red alert' emphasizes the need for continued vigilance following the outbreak declared in April. Adding to the regional picture, **New Zealand** reported imported dengue cases, underscoring how international travel connects the health of different nations. These cases originated from Samoa, highlighting the need for travelers to be aware of health risks in their destinations and take precautions. ## Pertussis (Whooping Cough): Protecting the Vulnerable Pertussis, commonly known as whooping cough, is a highly contagious bacterial infection of the respiratory system. It spreads easily through airborne droplets from coughing or sneezing. The disease is characterized by severe coughing fits, often followed by a distinctive 'whooping' sound as the person inhales. It can be particularly dangerous, even fatal, for infants and young children, who may struggle to breathe during coughing spells. Vaccination, through the DTaP vaccine for children and Tdap for adolescents and adults (especially pregnant women), is the most effective way to prevent severe illness and protect vulnerable populations. **Guam** is experiencing ongoing pertussis transmission, with cases affecting a wide age range, including infants and unvaccinated or partially vaccinated individuals. Public health teams are actively conducting case investigations, contact tracing, and promoting vaccination, with a 'red alert' in place to signify the seriousness of the outbreak. **New Zealand** continues to manage a national pertussis epidemic that began in late 2024. While weekly case numbers have shown some fluctuations, transmission remains widespread. Infants under one year are identified as the most vulnerable group, reinforcing the critical importance of high vaccination coverage for all eligible individuals to prevent severe outcomes. The 'blue alert' indicates persistent activity that requires ongoing public health attention. In **Vanuatu**, pertussis transmission is declining from its peak in late 2025 but remains above outbreak thresholds. While a declining trend is positive, children, particularly those aged 1–9 and infants, remain at high risk, with many cases reported among unvaccinated or partially vaccinated individuals. Enhanced surveillance and catch-up immunization campaigns are vital to further bring the outbreak under control, maintaining a 'blue alert'. ## Measles: Global Travel Fuels Local Outbreaks Measles is a highly contagious viral disease that can lead to serious complications, including pneumonia, encephalitis, and even death. It spreads through the air when an infected person coughs or sneezes. Symptoms include a high fever, cough, runny nose, red eyes, and a characteristic rash. The measles-mumps-rubella (MMR) vaccine is highly effective in preventing measles and achieving herd immunity, which protects those who cannot be vaccinated (e.g., infants too young for the vaccine or individuals with compromised immune systems). **Australia** is currently dealing with measles cases primarily linked to international travel, particularly from Southeast Asia. New South Wales and Victoria have seen multiple cases, with some individuals infectious while in public places, leading to exposure alerts. These incidents highlight the risk of imported cases sparking local transmission, especially among under-vaccinated populations, leading to a 'red alert'. **New Zealand** has also reported locally acquired measles cases in Wellington, without direct links to overseas travel, suggesting potential community circulation. This has prompted widespread public health action, including contact tracing, exposure notifications, and free MMR vaccination for those aged 12 months and over in affected areas. This 'red alert' situation underscores the global nature of measles and the need for high vaccination rates even in countries with elimination status. Globally, countries like **Bangladesh** and **Japan** are also experiencing significant measles activity, with widespread surges and increasing case counts, respectively. These international outbreaks serve as a constant reminder of the importance of maintaining high MMR vaccination coverage everywhere to prevent re-establishment of the disease and protect against international spread. ## Rotavirus: Tackling Diarrhea in Children Rotavirus is a common cause of severe diarrhea and vomiting in infants and young children, leading to dehydration which can be fatal if not managed. It spreads easily through the fecal-oral route, often due to contaminated food, water, or surfaces. Improved hygiene practices and access to safe water and sanitation are crucial for prevention, alongside the rotavirus vaccine, which is highly effective in preventing severe forms of the disease. In **Kiribati**, a rotavirus outbreak continues to be monitored, though a declining trend has been observed since its peak in early March 2026. The majority of cases, particularly among children under five, are concentrated in South Tarawa. Health authorities are sustaining enhanced surveillance, promoting hygiene, and implementing community-level interventions to further curb transmission. The 'blue alert' signifies that while numbers are dropping, low-level transmission persists, requiring ongoing efforts. ## Other Noteworthy Health Updates Beyond these major alerts, other health concerns are being addressed across the region. In the **Federated States of Micronesia**, diarrheal activity continues in Chuuk State following Typhoon Sinlaku. Environmental factors and challenges in water safety contribute to ongoing transmission. A non-epidemic cholera case was confirmed, prompting intensified water, sanitation, and hygiene (WASH) efforts. An international **Hantavirus (Andes virus) cluster** linked to cruise ship travel has also raised global awareness. While hantaviruses are typically rodent-borne, the Andes virus is unique in its documented potential for human-to-human transmission. Eight cases, including three deaths, have been linked to the MV Hondius, with international contact tracing and precautionary isolation measures implemented across multiple countries, including French Polynesia and Australia. Despite the human-to-human transmission potential, the World Health Organization assesses the global public health risk as low, emphasizing vigilance and early detection. These diverse health challenges across the Pacific emphasize the dynamic nature of infectious diseases. Continuous monitoring, prompt public health responses, and community engagement are paramount. For individuals, staying informed, ensuring up-to-date vaccinations, practicing good hygiene, and seeking medical attention for symptoms are crucial steps in protecting both personal and community health.