A mosquito-borne disease that kills thousands of people every year could become a major threat in the US, the World Health Organization has warned.
The agency’s chief scientist, Sir Jeremy Farrar, warned in an interview that dengue fever could emerge in the southern US and southern Europe before the year 2030.
He warned that global warming, which allows mosquitoes that can transmit the disease to move deeper into the country, would fuel the increase.
About 20,000 people die from dengue fever every year, mainly in Asia and South America, figures show. The disease has a mortality rate of one death per 100 patients.
About 1,200 cases are recorded in the U.S. each year, of which nearly 600 are locally acquired infections. But there are concerns the disease is spreading after California recorded its first locally acquired infection in a decade last month.
The above map shows the spread of dengue in the year 2020 across the world. More cases are now emerging in the US
Scientists say dengue fever could become endemic in the US if infected mosquitoes in Mexico manage to move further north.
They also warn that infected travelers entering the US could introduce the virus if they are bitten by local mosquitoes, which then become infected and transmit the disease to other people.
The disease is transmitted by the Aedes aegypti mosquito, already found in some parts of the south, which is active all day and can breed even in the smallest waterholes.
Doctor Farrar said Reuters: ‘We need to talk about dengue much more proactively.
‘We really need to prepare countries for how they will deal with the extra pressure that will come to many large cities in the future.’
He added: ‘Clinical care is very intensive and requires a high number of nurses and patients. “I’m really concerned if this becomes a major problem in sub-Saharan Africa.”
Dr. Farrar previously worked on tropical diseases, including dengue fever, in Vietnam for 18 years.
He later led the global health organization Wellcome Trust and advised the UK government on its response to the Covid pandemic before joining the WHO in May this year.
Outbreaks of dengue already occur in the United States, although they are “relatively small and limited,” according to the Centers for Disease Control and Prevention (CDC).
But experts warn the disease could spread more thanks to rising temperatures.
Dengue fever is a viral infection caused by a virus transmitted to humans when they are bitten by mosquitoes.
Most patients have no symptoms, but just under half will develop warning signs of the disease, including sudden headaches, fever and pain behind the eyes.
It can also cause pain in the joints – such as knees and elbows – that is so severe that it feels like they are being crushed, earning it the nickname “breakbone fever.”
In severe cases, the disease leads to life-threatening complications such as dengue shock syndrome – characterized by severe bleeding – and encephalitis, or swelling of the brain.
Doctors treat patients with a combination of painkillers, fluids and machines to monitor the disease.
But this is labor intensive and often leaves hospitals with little bandwidth to treat other patients.
There is also a vaccine available against the disease called Qdenga, which is recommended for children aged six to sixteen years old in areas where the disease is endemic.
The US Food and Drug Administration (FDA) has yet to sign off on the rollout of the vaccine in the United States, while its maker – Takeda Pharmaceuticals – is still in discussions.