Reality bites: Why the global dengue epidemic matters to Australia

The mosquito-borne disease is more than a health emergency – it symbolises the injustice of climate change.

Philippa Nicole Barr

16 September 20254 min read

Dengue fever is surging worldwide.

Dengue – the world’s most widespread mosquito-borne viral disease, causing an estimated 390 million infections annually across more than 100 countries – is surging in scale and severity. It is transmitted by Aedes mosquitoes, which thrive in urban water storage. In 2024, Brazil recorded nearly 5.8 million cases, seven times the number of Covid-19 infections in the same period, and there have been similar record outbreaks across Asia. The World Health Organisation now considers dengue one of the most important mosquito-borne diseases of humanity, with close to half the global population living in at-risk regions.

This wave has reached the Pacific: the most severe outbreak in a decade has claimed 19 lives, with Kiribati, Nauru, Samoa, and Tuvalu declaring emergencies. On Nauru, nine asylum seekers contracted dengue, including one man evacuated to Australia for treatment. Australia has pledged more than $1 million in emergency funding, including insecticides, test kits, and the deployment of an Australian Medical Assistance Team (AUSMAT) alongside a team from New Zealand. But is this the best approach?

While very hot regions may see transmission decline, cooler areas such as coastal and northern Australia could become more vulnerable.

Dengue has long flared across the Pacific in cycles tied to ecological and social disruption. It first spread around the region through colonial trade networks in the 19th century, and spread further during the Second World War as troop movements carried the virus across islands. In Australia, post-war infrastructure such as piped water and screened rainwater tanks eliminated dengue from Brisbane by the 1950s. Pacific Island states, by contrast, transitioned from colonisation to independence with fragile health systems and little investment in sanitation. Rapid urbanisation without adequate sanitation or piped water creates ideal breeding grounds. A single uncovered water tank can seed an epidemic.

A warming climate is playing a key role in dengue’s current resurgence. Anthropogenic climate change has already raised dengue incidence by an estimated 18% across Asia and the Americas, and some countries could face increases of up to 200% by mid-century. Some models predict that the global population at risk of dengue will rise from 53% in 2015 to 63% by 2080. The impact will not be uniform, however: while very hot regions may see transmission decline, cooler areas such as coastal and northern Australia could become more vulnerable. The Intergovernmental Panel on Climate Change has repeatedly warned that vector-borne diseases will proliferate in a warming world.

A worker sprays mosquito repellent as part of a prevention campaign against dengue fever in Banda Aceh on October 27, 2023. (Photo by CHAIDEER MAHYUDDIN / AFP) (Photo by CHAIDEER MAHYUDDIN/AFP via Getty Images)

Vector control methods such as insecticide spraying are challenging and resource-intensive at scale (Chaideer Mahyuddin/AFP via Getty Images)

The hard truth is that there are few easy solutions. There is no effective cure for dengue, and vaccines remain limited in scope. Treatments manage symptoms rather than halt progression, while vector control methods, including insecticide spraying, genetic modification, and novel Wolbachia bacteria releases, are challenging and resource-intensive at scale.

In September, Australia’s $1 million pledge and Minister for International Development Anne Aly’s statement that the response was “backing the leadership and priorities of our Pacific neighbours”, signalled a rhetorical shift towards partnership. Programs such as PacMOSSI, launched in 2020, aim to build local capacity through training, laboratory support, and national dengue action plans. Yet choosing the right intervention is a challenge. Following the dengue outbreak in the offshore detention centre on Nauru, human rights organisations were critical of a lack of basic preventative and treatment measures such as mosquito nets and Panadol.

Protective clothing, repellents, and screened housing help at the individual and household level. More critical are reliable water and sanitation systems, combined with community action to eliminate mosquito breeding sites. Without such measures, external aid will always be chasing the next crisis rather than stopping it at the source.

Each outbreak, whether in Suva or Cairns, is a reminder of shared vulnerability in a warming world.

For Australia, dengue is both a health and a security concern. Northern Queensland still battles small outbreaks seeded by travellers, while in the Pacific the disease is becoming an arena of geopolitical competition. On the same day Canberra announced its aid package, China publicised its own shipments of medical supplies and vector-control equipment to Samoa, Tonga, Vanuatu, and Fiji. In Vanuatu the local health ministry and a Hong Kong-based foundation launched a two-year program to repress vector-borne diseases, a project linked to the Belt and Road Initiative. Australia’s traditional role as the region’s health partner is no longer uncontested.

Pacific leaders frame dengue as more than a health emergency: it symbolises the injustice of climate change. Island nations produce only 0.03% of global emissions, yet face rising seas and worsening climate-driven disease burdens. Australia’s emergency deployments are welcome, but they do not address the ecological and infrastructural conditions that allow dengue to thrive. If Australia limits itself to crisis response, it risks ceding influence and failing to reduce the long-term risk to itself. To truly compete, Australia must renew its climate commitments and support infrastructure that addresses the root drivers of transmission.

Each outbreak, whether in Suva or Cairns, is a reminder of shared vulnerability in a warming world. By aligning health aid with meaningful climate action and infrastructure development, Canberra can move beyond symptom management towards genuine prevention. Meeting this challenge requires more than emergency relief: it demands a sustained commitment to reducing carbon emissions, Pacific development, and resilience across the Indo-Pacific.

About the author

Philippa Nicole Barr

Philippa Nicole Barr currently lives and works in Sydney, Australia.

Topics

Australia Pacific Islands Fiji Naoero Samoa Tonga Tuvalu Climate & environment