A mosquito-borne disease that kills thousands of people each year could become a major threat in the United States, the World Health Organization has warned.
The agency’s chief scientist, Sir Jeremy Farrar, warned in an interview that dengue could spread to the southern United States and southern Europe before 2030.
He warned that rising temperatures, which would allow mosquitoes that can transmit the disease to travel further into the country, would fuel the increase.
According to figures, about 20,000 people die every year from dengue, mainly in Asia and South America. The disease has a fatality rate of one death per 100 patients.
About 1,200 cases are recorded in the United States each year, of which almost 600 are locally acquired infections. But there are concerns the disease is spreading after California last month recorded its first locally acquired infection in a decade.
The map above shows the spread of dengue in the year 2020 around the world. More cases are now appearing in the US.
Scientists say dengue could become endemic in the United States if mosquitoes infected in Mexico manage to move further north.
They also warn that infected travelers entering the United States could introduce the virus if they are bitten by local mosquitoes, which then become infected and begin transmitting the disease to other people.
The disease is transmitted by the Aedes aegypti mosquito, which is already found in some southern areas, which is active at all hours and can reproduce even in the smallest puddles of water.
Dr. Farrar said Reuters: ‘We need to talk much more proactively about dengue.
“We need to really prepare countries for how they will deal with the additional pressure that will come… in the future in many, many big cities.”
He added: ‘Clinical care is really intensive and requires a high nurse-to-patient ratio. “I’m really worried that this will become a big problem in sub-Saharan Africa.”
Dr Farrar previously spent 18 years working on tropical diseases, including dengue, in Vietnam.
He later ran the global health charity Wellcome Trust and advised the UK government on its response to the Covid pandemic before joining the WHO in May this year.
Dengue outbreaks are already occurring in the United States, although they are “relatively small and limited,” according to the Centers for Disease Control and Prevention (CDC).
But experts warn that the disease could take hold thanks to rising temperatures.
Dengue is a viral infection caused by a virus that is 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, such as a sudden headache, fever and pain behind the eyes.
It can also cause pain in joints, such as the knees and elbows, that is so intense that it feels like they are shattered, earning it the nickname “bone-breaking fever.”
In severe cases, the disease causes life-threatening complications, such as dengue shock syndrome, characterized by severe bleeding, and encephalitis, or inflammation of the brain.
Doctors treat patients using a combination of pain relievers, fluids, and machines to control the disease.
But this is labor-intensive, often leading to hospitals having little bandwidth to care for other patients.
There is also a vaccine available for the disease, called Qdenga, which is recommended for children aged six to 16 years in areas where the disease is endemic.
The U.S. Food and Drug Administration has not yet approved the vaccine for rollout in the United States, and its manufacturer, Takeda Pharmaceuticals, is still in talks.