Dengue will 'take off' in southern Europe, US, Africa this decade, WHO scientist says

LONDON (Reuters) – Dengue fever will pose a significant threat in the southern United States, southern Europe, and new parts of Africa in the coming years, according to the chief scientist of the World Health Organization (WHO). This is due to the warmer temperatures creating favorable conditions for the spread of mosquitoes that carry the infection.

The disease has been a persistent problem in many regions of Asia and Latin America, causing an estimated 20,000 fatalities annually. The global incidence of dengue has already increased eightfold since 2000, primarily driven by climate change, population movement, and urbanization.

Although many cases go unreported, there were approximately 4.2 million reported cases worldwide in 2022, and public health officials are warning of near-record levels of transmission this year. Bangladesh is currently experiencing its worst outbreak, with over 1,000 deaths.

Jeremy Farrar, an infectious diseases specialist who joined the WHO in May, emphasized the need for proactive discussion on dengue. He stated, “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.”

Farrar, who had previously worked on tropical diseases in Vietnam for 18 years, served as the head of the Wellcome Trust global health charity and provided advice to the UK government on its COVID-19 response. He expressed concern that dengue would become endemic in parts of the United States, Europe, and Africa—regions that have already experienced localized transmission—as global warming expands the habitats suitable for disease-carrying mosquitoes. This could place significant strain on healthcare systems in numerous countries.

Severe dengue cases are relatively rare, with less than 1% resulting in fatality. However, the majority of infected individuals do not show symptoms, leading to even higher estimated case rates than reported. Those who do exhibit symptoms may experience fever, muscle spasms, and debilitating joint pain known as “break-bone fever.” Treatment options for dengue are currently limited, although a vaccine called Qdenga, manufactured by Takeda Pharmaceuticals, is recommended by the WHO for children aged 6 to 16 in areas where the infection is a significant public health concern.

The Qdenga vaccine is approved by the EU regulator, but Takeda withdrew its application in the United States earlier this year due to data collection issues. The company is still in discussions with the U.S. Food and Drug Administration regarding the vaccine.

Farrar emphasized the importance of allocating public health funds to the appropriate areas in order to prepare new regions for dengue. This would involve implementing effective mosquito control measures, as dengue is transmitted by Aedes aegypti mosquitoes, which behave differently from the malaria-carrying variety. For instance, they predominantly bite people indoors and throughout the day instead of during the night. They also breed in shallow water sources. Farrar stressed that comprehensive prevention strategies would include hospital triage plans, scientific advancements, and urban planning to mitigate the presence of standing water near or in households.

He concluded, “We need to combine different sectors that are not used to working together.”

Keep up with the latest medical breakthroughs and healthcare trends with our newsletter Reuters Health Rounds. Sign up here.

(Reporting by Jennifer Rigby, editing by Michele Gershberg and Sharon Singleton)