Epidemic and emerging disease alerts in the Pacific as of 1 July 2025

Highlights/updates since the last map was sent on PacNet on 24 June 2025:

Dengue

• Cook Islands: The Ministry of Health has officially declared a dengue fever outbreak in Rarotonga on 22 May 2025. Since February, there have been 35 dengue cases reported. 27 dengue cases have fully recovered with 8 cases currently active. Of the four samples with confirmed serotypes, three are Dengue Virus Type 1 (DENV-1) and one is Dengue Virus Type 2 (DENV-2), indicating co-circulation of DENV-1 and DENV-2. Stakeholder meetings are underway, and an island-wide clean-up and peri-focal spraying will continue for two weeks. No travel restrictions are in place, but precautions are advised. The public is urged to eliminate mosquito breeding sites, use repellents, wear long sleeves, and seek medical care if symptoms appear. The red alert for DENV-1 and DENV-2 is maintained. – Sources: Exchange with country focal person, Mitiaro prepares for Te Maeva Nui amidst dengue concerns in Rarotonga and Cook Islands 2025 Dengue Type 1 - Outbreak accessed on 1 July 2025.
• French Polynesia: In EpiWeek 25, 29 new dengue cases (24 confirmed and 5 probable) were reported. Since November 27, 2023, a total of 2,233 cases have been recorded, including 1,999 confirmed and 234 probable cases. Two new hospitalisations were reported in EpiWeek 25. The positivity rate increased, and hospitalisation rate decreased compared to EpiWeek 24. The blue alert for DENV-1 is maintained. – Source: Bulletin de surveillance sanitaire de Polynésie française n°23 - 2025 shared with focal point on 1 July 2025.
• Samoa: As of 22 June 2025, the Ministry of Health reported 166 lab-confirmed dengue cases in EpiWeek 25 (16 – 22 June 2025) bringing the total number of confirmed cases to 563 and one reported death since the declaration of the outbreak on 17 April 2025. The majority of cases (82%) are from Upolu Island, with 54% male and 46% female. Most cases are distributed across the Apia Urban Area and North West of Upolu regions, with individuals under 20 years old (86%) being the most affected. 14% of cases required hospitalisation, and of these admissions, 88% have been discharged. Of the 20 cases with confirmed serotypes, 85% are DENV-1 and 15% are DENV-2. The Ministry of Health continues collaboration across sectors through a whole-of-government approach via the Integrated Vector Control Committee. Current response efforts are focused on source reduction and environmental sanitation measures, ongoing risk communication on dengue preventative measures on all media outlets while urging the public to wear long-sleeved clothing to minimize risk of infection, use mosquito nets and repellents, remain vigilant for severe symptoms and to seek medical attention immediately when necessary. The red alert for DENV-1 and DENV-2 is maintained. – Source: Dengue Fever Situational Report #10 (22 June 2025) shared with focal point on 29 June 2025.
• Tonga: As of 27 June 2025, the Ministry of Health reported five new dengue cases, bringing the total confirmed cases to 884 since the declaration of the Outbreak on 19 February 2025, primarily affecting 10-19-year-olds. To date, three dengue-related deaths have been reported, with no patients currently hospitalised. Authorities continue case investigations, vector control at hot spot areas and public awareness efforts, urging residents to eliminate breeding sites, use protective measures, and seek medical attention for severe symptoms. The serotype that is responsible for this current outbreak is Dengue Virus Type 2 (DENV-2) identified by the Victorian Infectious Diseases Reference Laboratory (VIDRL), Melbourne Australia. The red alert for DENV-2 is maintained. – Source: Dengue Fever Outbreak, Situation report #63 (27 June 2025) shared with focal point on 28 June 2025.
• Tuvalu: The Tuvalu Department of Health declared a dengue outbreak on June 5, followed by the release of a dengue alert. As of 13 June 2025, there are 2 confirmed dengue cases and 1 probable case. One case has been identified as Dengue Virus Type 2 (DENV-2). The Ministry urges the public to take immediate precautions to prevent mosquito breeding sites and bites. These measures include eliminating standing water, using mosquito nets and repellents, wearing long-sleeved clothing, keeping surroundings clean and to seek medical attention when symptoms arise. The red alert for DENV-2 is maintained. Source: Exchange with focal person on 1 July 2025.

Influenza

• French Polynesia: In EpiWeek 25, 2 new influenza cases (type B) were reported including one hospitalisation. Since EpiWeek 03 2025, 593 influenza cases were reported with a total of 193 hospitalisations and twelve deaths. The positivity rate decreased, and hospitalisation rate is relatively stable during this reporting period. Influenza B is the predominant strain in circulation. The blue alert for influenza B is maintained. – Source: Bulletin de surveillance sanitaire de Polynésie française n°23 - 2025 shared with PPHSN Coordinating Body focal point on 1 July 2025.

Pertussis/Whooping cough

• New Zealand: As of week ending on 20 June, weekly pertussis cases in New Zealand decreased to 31 from 49 in week ending on 13 June, bringing the total reported cases since the beginning of 2025 to 1,497. According to the latest report from the New Zealand Institute for Public Health and Forensic Science (PHF Science), 2,448 confirmed, probable and suspect cases have been notified since the start of the national epidemic on 19 October 2024. Of these, 213 cases (9.1%) have required hospitalisation with one reported death. 101 (49%) out of the 211 cases in infants under 1 year are hospitalised. The blue alert is maintained. – Sources: Pertussis dashboard and Pertussis Report 3-30 May 2025 accessed on 1 July 2025.

Other Information:

Chikungunya

• Réunion Island and Mayotte: The ongoing chikungunya epidemic in Réunion Island is decreasing with the virus circulating in limited municipalities. Since the beginning of the year, 54,242 confirmed cases, 2,836 visits to the emergency room, 577 hospitalisations and 27 deaths linked to chikungunya have been reported. The vaccination campaign which began on April 07 remains available for those aged 18 to 64 with comorbidities. Health Authorities emphasize monitoring for allergic reactions within 72 hours of vaccination and seeking immediate medical attention if symptoms occur. Health authorities are urging heightened vigilance for travelers to La Réunion, visitors are advised to take preventive measures against mosquito bites, including the use of insect repellent, wearing long-sleeved clothing, and staying in accommodations with screened windows or air conditioning. In Mayotte, the chikungunya virus is actively circulating, with 1076 confirmed cases and thirty-eight hospitalisations since the beginning of the year. Returning travelers may pose a risk of introducing chikungunya to other regions, where Aedes mosquito vectors are present. It is recommended that returning travelers from Indian Ocean islands monitor for symptoms (fever, joint pain, rash) for up to two weeks and seek medical attention if symptoms arise. - Sources: Chikungunya : Les autorités sanitaires retirent les personnes de 65 ans et plus des cibles de la campagne de vaccination contre le chikungunya avec le vaccin IXCHIQ à La Réunion et à Mayotte, Bulletin D'information Chikungunya 27/06/2025 and Chikungunya à La Réunion : semaine du 16 au 22 juin 2025 accessed on 1 July 2025.

Measles

• Australia: In Australia, the New South Wales Health is urging the public to be alert for signs and symptoms of measles following notification of a confirmed case who was infectious while visiting several locations in Sydney. The individual recently returned from Vietnam where a large measles outbreak is currently ongoing. People who visited the following locations, Sir Reuben, 702 Darling St, Rozelle on Sunday 22 June from 12-1pm and Concord Hospital Emergency Department from 10.35pm-3.10am, are advised to monitor for symptoms up to 18 days after exposure and to contact their GP if symptoms develop. - Source: Measles alert for Sydney accessed on 1 July 2025.
• United States: In the United States, the CDC reported a total of 1,227 measles cases across 37 U.S. jurisdictions, as of 24 June with 89% of these cases linked to twenty-three outbreaks. The majority of cases are among unvaccinated individuals (95%), and 12% of the cases have resulted in hospitalization. There have been three confirmed deaths. The 37 jurisdictions that have reported measles cases are as follows, Alaska, Arkansas, Arizona, California, Colorado, Florida, Georgia, Hawaii, Illinois, Indiana, Iowa, Kansas, Kentucky, Louisiana, Maryland, Michigan, Minnesota, Missouri, Montana, Nebraska, New Jersey, New Mexico, New York City, New York State, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, and Washington. - Source: Measles Cases and Outbreaks accessed on 1 July 2025.