States battling outbreak of 'bone-breaking' virus brought in from Asia and Africa

Hawaii has reported a dozen cases of 'bone-breaking' dengue fever, prompting urgent warnings from health officials.

The Hawaii Department of Health this week confirmed a case of dengue fever on the island of Oahu in a resident who contracted it during international travel.

It's unclear exactly where the individual traveled, but the health department said it was a region where dengue is common, such as southeast Asia, South America, the Caribbean or Africa.

This brings the state's total for 2025 to 12, which is already approaching the total of 16 reported in the entirety of last year.

So far in 2025, the CDC has confirmed 2,725 cases of dengue fever across 46 states and territories, most of which were locally acquired within the US. Dengue is most common in six states, and the CDC reports of locally acquired cases in Florida, Texas, Hawaii, Arizona and California.

While cases have been on the rise in years past, figures are slowing after a dengue outbreak last year resulted in a record-high 8,000 infections.

Spread by bites from infected mosquitoes, the disease has been nicknamed 'break-bone fever' because sufferers say their joints and muscles can become so painful it feels like their bones are breaking.

And about one in 20 people with symptoms suffer bleeding, gasping for air and shock.

All cases detected in Hawaii so far have been in people who traveled to regions where dengue is more common, so the agency warned people returning from endemic areas contact their doctor if they develop symptoms within two weeks.

Mosquitoes carrying the dengue virus are usually found in tropical and subtropical regions like Central and South America, Africa, South Asia and the Pacific Islands.

In the US, dengue is most prevalent in Florida, Texas and California, as well as the territory Puerto Rico.

According to CDC data, Puerto Rico has reported the most dengue cases at 2,152 so far this year. Florida has seen 115 cases while California has seen 62.

The disease spreads through mosquito bites and cannot be transmitted from person to person.

Roughly 400million people get dengue fever every year but eight in 10 don't develop any symptoms.

Those who do usually experience a high fever, blotchy rash, muscle aches, joint pain and pain behind the eyes.

But in rare and severe cases, the condition can cause vomiting or throwing up blood, intense joint pain and trouble breathing. These issues may further cause internal bleeding, leading to death.

Thirteen percent of patients die from the disease if they do not receive treatment.

There is no antiviral for dengue fever, but the World Health Organization says that by rapidly replacing lost fluids the mortality rate drops to less than one percent.

A vaccine for dengue is available and approved by the FDA for children aged nine to 16 years old, but its manufacturer, French pharma giant Sanofi Pasteur, has discontinued production globally, citing a lack of demand.

Doses are available in Puerto Rico, but these are expected to run out by 2026.

Dengue cases have surged in Latin America, thought to be linked to the El Nino weather cycle at that time - which brings more heavy rains to areas of the continent - leading to more standing water in which mosquitoes can multiply.

At the same time, rising temperatures have allowed mosquitoes to be active for longer each year and advance further north.

In areas of the world where outbreaks are not as common, upticks are being linked in part to travel, leading to people who become infected abroad to enter the US then get bitten by a mosquito, which passes the virus to the insect and allows it to take root in the local mosquito population.

The CDC urges Americans traveling to high-risk areas to carry insect repellent, wear long sleeves and long pants outside and sleep in air-conditioned rooms or those with window screens to prevent being bitten.