Written by PhD candidate, Wil Laura.

Dengue fever is spreading faster than ever. In 2024, the world recorded 14.1 million cases, double the number from just a year earlier.

Peru shows just how quickly the potentially deadly disease can rise. Peru went from only 15,000 dengue cases in 2019 to more than 250,000 in 2023.

I have been researching Peru, one of the countries hardest hit by dengue, to understand how climate and weather conditions drive outbreaks.

What my colleagues and I found offers valuable lessons for Australia, where dengue has already made its presence felt.

What is dengue fever?

Dengue is a mosquito-borne viral disease. The most common symptom is fever, often accompanied by eye pain, muscle or bone aches, nausea, and rash, lasting between two and 7 days.

Most people recover fully, but in some cases the illness can progress to severe dengue, which can be life-threatening without timely medical care.

Given the global incidence of dengue is so high, this can result in tens of thousands of deaths in a year.

The spread of dengue depends heavily on the weather. Warmer temperatures help mosquitoes develop faster, feed more often, and in the right conditions live longer. Rain provides breeding sites, while humid air helps mosquitoes survive and stay active, together creating ideal conditions for them to multiply.

Because dengue incidence is closely tied to the climate, scientists like myself can use climate thresholds, such as certain levels of heat, rainfall, or humidity, to help predict when outbreaks are more likely in the weeks ahead.

What does Peru’s case study tell us?

In our new research published in the Journal of Climate Change and Health, we found that dengue cases in Peru can surge more than 50-fold when temperature, rainfall, and humidity cross specific thresholds.

We found that these climatic thresholds differ across Peru’s diverse climate zones, from arid deserts to rainforest biomes, highlighting the strong influence of local weather conditions on outbreak dynamics.

The study analysed 22 years of climate and health data (2001–2022) from regions with the highest dengue incidence. Using a fine-tuned regression tree model, the researchers identified weather patterns that often appeared up to 20 weeks before outbreaks.

These insights suggest that dengue surges can be forecast weeks in advance using climatic data, offering a valuable early warning tool for public health planning and mitigation.

What about dengue fever in Australia?

Most dengue cases in Australia have been in travellers who caught the disease overseas, known as imported cases. Between 2012 and 2022, Western Australia and New South Wales recorded the highest numbers of these cases.

However, the risk of local outbreaks remains, especially in northern regions such as Queensland and the Northern Territory, where warm and wet conditions favour mosquitoes.

During this period, Australia reported 13,343 dengue cases, more than twice the number from the previous decade.

The peak of locally acquired cases came in 2013, with Queensland accounting for 560 cases (96 per cent of that year).

Effective mosquito control programs helped reduce local transmission over the following years, and no locally acquired cases were reported in 2021 and 2022. Despite this progress, locally acquired dengue has reappeared in recent years, including in Queensland in early 2025.

There are a few things you can do as an individual to help protect yourself from dengue. Try to get rid of stagnant water where mosquitoes breed, use insect repellents or sprays, and cover up with clothing to avoid bites.

As the planet warms, more parts of Australia may become suitable for dengue-carrying mosquitoes. This means a higher chance of outbreaks in the future.

For now, mosquito control and prevention have been effective in limiting spread within Australia. But with climate change raising the risks, health systems will face growing pressure to prevent dengue outbreaks.

The big picture? The best way to stop diseases like dengue from spreading further is to limit global warming by cutting greenhouse gas emissions.

At the same time, enhancing the monitoring of climate conditions and dengue thresholds will be key to protecting communities and preparing for future outbreaks in Australia.