## Health Alerts Across the Pacific: A Regional Overview The vast and diverse Pacific region is currently navigating a range of public health challenges, with several infectious diseases under close surveillance by health authorities. From mosquito-borne illnesses like dengue fever to highly contagious respiratory infections such as pertussis, and the persistent threat of polio, vigilance and proactive public health measures remain crucial. Recent updates from early May 2026 highlight the ongoing efforts to manage and prevent the spread of these conditions, ensuring community safety and well-being. ### Dengue Fever: A Persistent Threat in Tropical Climates Dengue fever, a viral illness transmitted through the bite of infected *Aedes* mosquitoes, continues to pose a significant health burden across many Pacific island nations. Characterized by sudden high fever, severe headache, pain behind the eyes, joint and muscle aches, and a rash, dengue can sometimes progress to a more severe form, requiring urgent medical attention. Public health advisories often use ‘alert levels’ to communicate the severity of outbreaks, with 'red alert' indicating widespread and escalating transmission. **New Caledonia** is currently under a red alert for dengue, specifically DENV-1, signifying continuous transmission. As of early May 2026, the territory had reported 1,376 cases for the year, showing a sustained increase since previous updates. The presence of a predominant serotype like DENV-1 is important for understanding potential future risks, as prior infection with one serotype does not protect against others and can sometimes lead to more severe disease if infected subsequently by a different serotype. Efforts to control mosquito populations and raise public awareness are paramount in managing such outbreaks. Further west, **Samoa** is also battling ongoing dengue transmission, now under a blue alert for both DENV-1 and DENV-2, indicating continued circulation. In one week alone in April 2026, 159 new cases were identified, with children under 15 years disproportionately affected, accounting for 74% of cases. The co-circulation of two different serotypes adds complexity to the public health response, as it increases the risk of more severe outcomes. Sadly, the cumulative number of dengue-related deaths in Samoa remains at nine, underscoring the serious nature of the disease, even as officials observe a slight decrease in confirmed infections compared to the previous week. **Tonga** initiated an outbreak response for dengue in April, and transmission continues to be reported. By early May, 53 laboratory-confirmed cases had been documented, with three new cases identified in a single day. The DENV-2 serotype is predominant, and children aged 10-14 years, particularly males, are the most affected group. Most infections were reported from Tongatapu island. Three individuals were hospitalized, though no dengue-related deaths have been recorded. A red alert remains in effect for DENV-2, prompting intensified surveillance and public health interventions. Even **New Zealand**, a non-tropical nation, reported five confirmed imported dengue cases in a single week in late April/early May 2026. These cases had travel histories to other Pacific islands, including the Cook Islands, Samoa, and Tonga, as well as Malaysia, highlighting how interconnected the region is through travel and the potential for disease importation. This underscores the need for robust border surveillance and public health messaging for travelers. ### Pertussis (Whooping Cough): A Threat to the Unvaccinated Pertussis, commonly known as whooping cough, is a highly contagious respiratory infection caused by the bacterium *Bordetella pertussis*. It is particularly dangerous for infants and young children, often leading to severe coughing fits, difficulty breathing, and sometimes life-threatening complications like pneumonia or seizures. Vaccination is the most effective way to prevent pertussis, which spreads easily through airborne droplets from coughing or sneezing. In the **Federated States of Micronesia (FSM)**, Pohnpei State is experiencing ongoing pertussis transmission, currently under a blue alert. In one week in April 2026, four new cases were reported, bringing the cumulative total to 40 cases since January. Young children and unvaccinated individuals remain most vulnerable, prompting health authorities to maintain enhanced surveillance, contact tracing, and vaccination activities, alongside community awareness campaigns. **Guam** is under a red alert for pertussis, reflecting persistent transmission. Since May 2025, 23 cases have been detected, with three new cases identified in April 2026. While no hospitalizations or deaths have been reported, public health efforts are focused on case investigation, contact tracing, and targeted vaccination for high-risk groups, including infants, pregnant women, and close contacts of confirmed cases. The severity of the alert emphasizes the need for rapid response to contain further spread. Across the Tasman Sea, **New Zealand** also shows ongoing pertussis activity, with a blue alert in place. The week ending April 24, 2026, saw 38 new cases, contributing to a total of 610 cases reported in 2026. Weekly notifications fluctuate, indicating sustained community transmission. While vaccination rates in New Zealand are generally high, the continuous circulation of the bacteria highlights the importance of maintaining herd immunity and ensuring timely booster shots. ### Polio: Global Eradication Efforts and Environmental Surveillance Poliomyelitis, or polio, is a crippling and potentially fatal infectious disease caused by the poliovirus. It primarily affects young children and can lead to irreversible paralysis. Thanks to global vaccination efforts, wild poliovirus cases have dramatically decreased worldwide. However, outbreaks of vaccine-derived poliovirus (VDPV), which can emerge in under-vaccinated populations where the weakened live virus in oral polio vaccines circulates and mutates, still pose a threat. **Papua New Guinea (PNG)** continues its sustained response to a national poliovirus outbreak, declared in May 2025, and is currently under a red alert. While no new human poliovirus cases have been reported since October 2025 following two nationwide vaccination rounds, recent environmental samples have detected poliovirus signals. This 'silent circulation' means the virus is present in the environment without causing visible paralysis cases, requiring heightened vigilance. To interrupt transmission, PNG launched its third round of a polio vaccination campaign in late April 2026, targeting children aged 0-59 months, especially in provinces with lower coverage such as Morobe, Enga, the National Capital District, and Central Province. The goal is to achieve at least 95% vaccination coverage. Further illustrating the importance of environmental surveillance, **Australia** detected vaccine-derived poliovirus type 2 (VDPV2) in a wastewater sample in Perth, Western Australia, in mid-April 2026. This was an environmental detection only, meaning no clinical cases were found, and there was no evidence of local transmission. Australian health authorities assess the risk to the community as very low due to high polio vaccination coverage and the country's polio-free status since 2000. Nevertheless, follow-up wastewater testing has been intensified, and public health officials continue to reinforce vaccination messages. ### Other Monitored Health Concerns: Diarrhoea, Hantavirus, and Mpox Beyond these major alerts, public health systems are also tracking other emerging and ongoing issues: **Diarrhoea** outbreaks are a common concern in many parts of the Pacific, often linked to issues with water, sanitation, and hygiene. In the **Federated States of Micronesia (FSM)**, Yap State reported an increase in diarrhoeal cases, with 19 cases in a single week in April 2026. Laboratory testing confirmed various enteric pathogens, including norovirus, rotavirus, and diarrhoeagenic *E. coli*. Public health authorities are promoting hygiene, food safety, and community awareness, while surveillance remains ongoing, especially in vulnerable outer island communities. A rare but serious event involving **Hantavirus** has been reported in connection with a cruise ship, MV Hondius, travelling from Argentina to the Canary Islands. A British passenger was critically ill in South Africa with a laboratory-confirmed case, and three suspected deaths occurred among other passengers. Hantaviruses are typically spread by rodents and can cause severe respiratory or kidney disease; human-to-human transmission is rare. The World Health Organization (WHO) is coordinating a multi-country response, emphasizing contact tracing and medical investigations. Despite the severity for those affected, the risk to the general public is assessed as low, with no travel restrictions recommended. Finally, **Mpox**, formerly known as monkeypox, continues to be monitored globally. In **Hawaiʻi**, clade I mpox virus was detected in wastewater on Oʻahu in April 2026, marking the first such detection in the state. Importantly, no clinical cases of clade I mpox have been identified, and there is no evidence of community transmission. Subsequent testing of wastewater samples was negative, and routine testing at civilian sites remains clear. Health authorities consider the risk to the general public low but encourage vaccination and vigilance among higher-risk groups, underscoring the value of wastewater surveillance as an early warning tool for public health. These varied alerts across the Pacific highlight the dynamic nature of public health and the critical importance of robust surveillance systems, rapid response teams, and sustained community engagement in vaccination and hygiene practices. Staying informed and adhering to public health advice are key to protecting individuals and communities from these ongoing health threats. ## Key Takeaways * **Stay Vigilant Against Mosquito-Borne Illnesses:** Protect yourself from dengue by eliminating mosquito breeding sites, using repellents, and wearing protective clothing, especially in areas with active outbreaks like New Caledonia, Samoa, and Tonga. * **Prioritize Vaccinations for Respiratory Diseases:** Ensure timely pertussis (whooping cough) vaccinations, particularly for infants, pregnant women, and close contacts, to protect vulnerable populations in regions like FSM, Guam, and New Zealand. * **Support Polio Eradication Efforts:** Participate in vaccination campaigns in affected areas like Papua New Guinea, and understand that environmental poliovirus detections, as seen in Australia and Hawai'i, underscore the need for continued high vaccination coverage and surveillance. * **Practice Good Hygiene for Digestive Health:** Prevent diarrhoeal diseases by ensuring access to safe drinking water, practicing proper handwashing, and maintaining food safety standards, crucial for communities like Yap State in FSM. * **Be Aware of Emerging Threats but Remain Calm:** While outbreaks like Hantavirus on a cruise ship or Mpox in wastewater are monitored, public health authorities often assess the general risk as low; follow official guidance for specific preventative actions.