British holidaymakers could be at greater risk of dengue fever when they travel to southern France, after a 44-year-old woman was infected there.

The tropical disease could be set to cause more outbreaks due to climate change, experts have warned.

Asian tiger mosquitos which carry the virus thrive in warmer temperatures, and there are concerns it is now an emerging health threat in the south of France.

The 44-year-old British woman, who has not been identified, was infected with dengue during a trip to a small village near Nice in September.

She had experienced fever, headaches, muscle pain and a red rash for three days but did not need any medical treatment and made a full recovery.

Tropical diseases like dengue, which causes 50 to 100 million cases a year across over 120 countries, may be heading our way in the long-term future, experts have warned. We could require wider use of public health control measures, such as mosquito nets or insect sprays. Asian tiger mosquitos which carry the virus thrive in warmer temperatures, and there are concerns it is now an emerging health threat in the south of France

Her case was presented at this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) in Copenhagen.

Dr Owain Donnelly, from the Hospital for Tropical Diseases in London, who presented it, said: ‘This individual was part of an outbreak of over 30 locally transmitted cases in the south of France in 2022, which highlights the rapidly changing epidemiology of dengue.

‘With climate change, particularly hotter temperatures and more rainfall, and increasing global trade and tourism, we may see more parts of Europe with the right combination of factors for dengue outbreaks.’

Southern France has the right combination of climate, a stable mosquito population and a high volume of travellers returning from trips to tropical countries to cause outbreaks.

It has had several dengue outbreaks in the past 15 years, but the most recent is the most severe yet.

As regards the threat to Britain, officials have detected Asian tiger mosquitos, whose scientific name is Aedes albopictus, at UK ports multiple times over the past few years, but no local populations have established in this country yet.

However tropical diseases like dengue, which causes 50 to 100 million cases a year across over 120 countries, may be heading our way in the long-term future, when we could require wider use of public health control measures, such as mosquito nets or insect sprays.

The British holidaymaker’s diagnosis was made by the UK’s Rare Imported Pathogens Laboratory (RIPL) after she visited A&E after returning home to the UK and doctors sent an urgent sample for analysis

Family members she stayed with in France also experienced similar symptoms.

Dengue fever, spread by the bite of infected mosquitos, causes no symptoms in an estimated three-quarters of cases, and often causes only mild flu-like symptoms.

But a small minority of people experience headaches, severe joint pain and even internal bleeding that can lead to death.

Between June and September 2022, the Agence Regionale de Santé (ARS) in France reported three separate outbreaks of dengue virus transmission contracted on national territory without patients having travelled abroad.

Dr Donnelly said: ‘To ensure accurate diagnosis, physicians should consider testing for dengue if patients live in or have visited countries where Aedes albopictus is found, and present with the typical constellation of symptoms, even if dengue is not widespread.

‘Making the correct diagnosis not only has an impact on patients, but also allows us to increase our understanding of dengue distribution and take appropriate steps to control outbreaks.’