In 2020–24, the Auckland district had a high mosquito-borne disease rate that was more than twice the national rate.
The findings come as mosquito-borne disease notifications increased from 122 cases in 2023 to 168 cases in 2024, driven largely by a rise in dengue infections among New Zealanders returning from overseas travel.
The report highlights the continued impact of international travel on the importation of mosquito-borne diseases into Aotearoa New Zealand. Most people diagnosed with dengue had recently travelled to countries in Southeast Asia and other parts of Asia, while malaria cases were associated with travel to Pacific nations and Africa.
EHINZ Senior Research Officer Dr Mui Nguyen says the findings reinforce the importance of awareness and prevention measures for people travelling overseas.
"The increase in dengue notifications reflects both the resurgence of international travel and the elevated dengue activity being reported in a number of countries across Asia.
“Travellers can reduce their risk by taking simple precautions such as using insect repellent, wearing long sleeves and trousers and staying in accommodation with appropriate mosquito protection."
Dengue accounted for the majority of mosquito-borne disease notifications in 2024 and was the primary driver behind the increase in cases. While these diseases are not established in New Zealand, imported cases can still place pressure on public health systems and highlight the importance of ongoing surveillance.
The report also identified notable differences across population groups. Rates of mosquito-borne disease were higher among males and Pacific peoples, while people living in more socioeconomically deprived areas experienced higher rates than those in the least deprived communities.
Auckland consistently recorded the highest rates of mosquito-borne disease during the five-year period analysed, reflecting both the region's large population and its role as New Zealand's main international gateway.
The findings underline the importance of monitoring travel-related infectious diseases and ensuring travellers are aware of health risks before departing overseas.
"Auckland's higher rates are not unexpected given it is New Zealand's largest city and the country's main gateway for international travellers. Monitoring these trends helps us identify emerging risks and better target public health messaging," Dr Nguyen explains.
Dr Nguyen says continued surveillance helps build a clearer picture of how mosquito-borne diseases affect New Zealanders and supports efforts to reduce the risk of infection through travel advice, public health messaging and early detection of cases.
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