Breakbone fever: Why travellers are being warned about deadly mosquito-borne illness Dengue

Travellers are being urged to take precautions overseas as global cases of the potentially deadly mosquito-borne illness known as “breakbone fever” continue to rise.

The US Centres for Disease Control and Prevention (CDC) has issued a Level 1 travel notice, warning of a “higher-than-expected” number of dengue cases in travellers returning home.

The alert applies to at least 16 countries, including Vietnam, Indonesia’s neighbour Timor-Leste, New Caledonia, Samoa, the Maldives, Cuba and Colombia, which are all popular or accessible destinations for Australian holidaymakers.

The CDC said the spike was detected through surveillance of returning travellers, with hundreds of cases already recorded in the United States this year, with the vast majority linked to overseas infections.

While the advisory is classified as Level 1, meaning travellers can still visit but should “practice usual precautions”, authorities are urging people to take the risk seriously.

Travellers are advised to use insect repellent, wear long-sleeved clothing and stay in screened or air-conditioned accommodation to avoid mosquito bites.

Dengue, commonly known as breakbone fever due to the severe muscle and joint pain it can cause, is a mosquito-borne virus widespread in tropical and subtropical regions.

Symptoms can include fever, nausea, rash and intense body aches, with around one in four infected people becoming unwell.

In more serious cases, the disease can escalate into severe dengue, causing internal bleeding, organ failure and, in rare cases, death — sometimes within hours.

There is no specific treatment for dengue, with care focused on rest, fluids and pain relief.

The warning is particularly relevant for Australians, with the Federal Government’s advice already noting that dengue outbreaks are occurring globally and that most infections recorded in Australia are acquired overseas.

Health authorities also warn people who have previously had dengue face a higher risk of severe illness if infected again.

Globally, dengue is spreading rapidly, with tens of thousands of cases already recorded across dozens of countries in early 2026 alone, underscoring the growing risk as international travel rebounds.

The US CDC alert reinforces a key message for Australians heading abroad: while the disease may not be widespread at home, the risk overseas is rising, and simple precautions could be critical.

What is ‘breakbone fever’?

Dengue, often called breakbone fever, is a virus spread by infected mosquitoes that can cause illness ranging from mild symptoms to “serious disease … and in some cases, it can cause death,” according to the Australian Centre for Disease Control.

“Infection with dengue virus can cause an illness ranging from mild symptoms to serious disease (such as dengue haemorrhagic fever or dengue shock syndrome). In some cases, it can cause death.

“People who have had dengue before can get infected again.

“A second infection with a different type increases the risk of severe dengue, so preventing mosquito bites is especially important for people who have had dengue before.”

How common is it?

Dengue is a “major global health concern, with millions of infections diagnosed every year around the world,” the Australian CDC says.

While it is not endemic in Australia, outbreaks do occur, particularly in northern Queensland and the Torres Strait.

Can it be treated?

“There is no specific treatment for dengue,” the Australian CDC warns.

Most people recover within a week, but severe cases can require hospital care. Patients are also advised to avoid anti-inflammatory drugs like ibuprofen due to bleeding risks.

What are the symptoms?

Common symptoms include fever, headache (often behind the eyes), muscle and joint pain, and rash. “Most people who have dengue recover in about a week,” Australia’s CDC website says.

In more serious cases, symptoms can escalate to “severe abdominal pain, rapid breathing, vomiting … and unexplained bleeding”.

Why travellers are most at risk

Australians are most likely to catch dengue overseas, particularly in parts of Asia, the Pacific, Africa and South America where the virus is widespread.

“People are more likely to be exposed … if they live in or are travelling to an area where dengue is common,” the Australian CDC says.

How it spreads

Dengue spreads through the bite of infected mosquitoes, which are commonly found in urban areas and bite during the day.

Importantly, “dengue does not transmit directly from person to person”.

How to protect yourself

With no widely available vaccine for first-time infections in Australia, prevention is key.

“The best protection is to prevent mosquito bites,” the Australian CDC says.