Once specific to small pockets of Asia, the infection can now be found across several continents of the world, say researchers.
Rising temperatures mean that nearly half the world’s population may now be at risk of dengue infection, new modelling forecasts.
Analysis from Airfinity, a science data analyst company, shows that the incidence of dengue has already increased by at least 30-fold over the past 50 years.
Half a million cases were reported to the WHO in 2000, rising to 5.2 million in 2019, with the true number of annual infections now estimated to be up to 96 million.
Once specific to small pockets of Asia, the disease is now considered endemic in more than 100 countries globally and its geographical reach is continuing to spread, according to the WHO.
Global warming is driving increasingly hotter and wetter climates in which mosquitos, the main transmitter of dengue, can survive, breed and further spread.
I caught the ‘bone-breaker’ fever headed for Europe – I was sick for days and my lips turned blue
The ‘Asian tiger’ mosquito has now been spotted or become established in 30 European countries, meaning dengue could soon be a UK problem. Sarah Newey explains what happened when she caught the virus in Thailand.
Dr Louise Blair, Airfinity’s Director of Analysis and Insights, warns that the threat posed by dengue must not be overlooked as cases continue to spread beyond the traditional tropical hotspots into the global north.
“In the short term, southeast Asia is at the greatest risk of further dengue outbreaks, but climate models show that increased mosquito transmission is expected in Europe”, she said.
“If temperatures continue to rise then we could see the disease becoming endemic in southern Europe. Innovation in vaccines, treatments and other countermeasures will define how dengue is handled.”
Mosquitoes on the march
Dengue is already on the rise in Europe. Its spread has notably increased across France over the past 12 years; it was identified in more than 70 regions in 2022, compared to just six in 2010.
Just last year, there were 65 detected cases of dengue in the country, compared with 48 in the past 12 years combined.
According to Airfinity, locally-acquired infections in France could reach 3,000 annually by 2030.
Cases of the virus have also been reported in Spain and Italy in recent years, and British experts believe it’s only a matter of time before it takes off in the UK, with health authorities now working to mitigate the spread of the virus.
The mosquito that carries dengue, the Aedes albopictus, is often transported into Europe via shipping containers or people’s cars.
In response, funding is being invested into mosquito trapping and monitoring systems at UK ports that aim to detect the insects.
Dengue fever: the key questions answered
What is dengue fever?
Dengue fever is a disease caused by the dengue virus and you can contract it through a mosquito bite – specifically, a species of mosquito that bites in the day. The virus is mainly present in tropical climates, but some cases have been found in European countries.
What are the symptoms and what should you look out for?
The majority of cases are asymptomatic or mild and can be treated at home. So do not let the dengue virus stop you from travelling, but be sure to take the right precautions.
It is unlikely you can tell if you have been infected with dengue from the bite alone, and an infection can be asymptomatic. However, according to the NHS, symptoms can emulate those of the flu, such as a high temperature, severe headache, pain behind the eyes, muscle and joint pain, feeling or being sick, swollen glands, and a blotchy rash made up of flat or slightly raised spots. Sometimes dengue can become more severe, however, in which case people will tend to display more severe symptoms.
What should you do if you suspect you have contracted dengue fever and what is the treatment?
For mild dengue, there is no specific treatment and the NHS recommends treating it as you would the common cold or flu. Advice given is to rest, drink plenty of fluids, and take paracetamol to offset any pain. However, for severe dengue, hospital treatment is required and you should seek medical help. The NHS includes severe tummy pain, being sick often, fast breathing, bleeding gums or nose, fatigue, restlessness, and blood in your vomit or poo as the symptoms to look out for.
How can you prevent catching dengue fever?
It’s as simple as preventing yourself from being bitten by mosquitoes. The dengue mosquito breeds in water-filled containers, so these should be correctly disposed of and/or cleaned. Wear clothing that covers the body, ensure windows and doors are closed, fit mosquito nets for during both day and night, and wear plenty of insect repellent that includes the active ingredient Deet.
How worried should I really be?
Dengue fever is not present in the UK, but the incidence rate has increased over past decades. Even so, the WHO stresses the rising threat of dengue and estimates between 50-100 million annual infections in over 100 endemic countries.
Dr Oliver Brady, Associate Professor at the London School of Hygiene & Tropical Medicine and an expert in mosquito-transmitted viruses, says that the numbers of infections across Europe can differ quite drastically between modelling projections – but this is expected due to the uncertainty surrounding climate change.
“It’s important to highlight the risk of large dengue outbreaks in Europe as a major problem,” he said.
“We might need to take travel precautions over the coming years when visiting parts of Europe, particularly the south Mediterranean. This isn’t just a big inconvenience, but a major risk.
“The threat probably isn’t imminent, but it’s certainly an acceleration risk across Europe, and that containment at the ports is only going to get more and more difficult.”
Many dengue infections are asymptomatic, but the virus can occasionally cause fever, body aches and a rash. Although most cases recover in one to two weeks, some can require hospital care and result in death; in total, 36,000 people die from the infection every year.
(Sources: The Telegraph)
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