Dengue, chikungunya on the rise due to climate change: WHO

Experts at the United Nations health agency warned on the rising number of cases of dengue and chikungunya, and warned that new epidemics of Zika could also be expected.

All three are caused by arboviruses carried by Aedes aegypti mosquitoes, which have spread to new areas as the planet warms.

“Climate change has played an important role in facilitating the spread of vector mosquitoes,” said Raman Velayudhan, who coordinates WHO’s dengue and arbovirus initiative.

He and his colleague Diana Rojas Alvarez, the WHO’s technical lead on chikungunya and Zika, stressed the need for urgent action to rein in the spread of mosquitoes amid fears of major outbreaks in new areas.

A total of 129 countries are already at risk from dengue, including 100 countries where the disease is endemic.

And the number of cases has risen sharply in recent years, Velayudhan told reporters, rising from about half a million in 2000 to about 5.2 million in 2019, the worst year on record.

The cases were not properly recorded during the Covid pandemic, but he warned that the numbers remain high.

In parallel, chikungunya, which to date has been reported in 115 countries since its discovery in 1950, is experiencing a dramatic surge in the Americas, Rojas Alvarez told reporters.

Around 135,000 cases have been reported so far this year, while 50,000 cases were reported during the first half of 2022, he added.

‘Dangerous’

Of most concern is the geographic expansion of both diseases, being further reported in South America and also increasing in the Northern Hemisphere, including several European countries.

Rojas Álvarez said, “With climate change, mosquitoes and these diseases are increasing … by altitude and latitude,” describing the situation as “alarming.”

“This high transmission (in the US) may be a predictor of what the next summer season in the Northern Hemisphere may look like,” she warned.

These two diseases often cause mild symptoms like fever, body aches and rash.

But most people with chikungunya have symptoms for about a week, while as many as 40 percent will feel the effects for months or years.

“It can cause lifelong disabilities,” warned Rojas Alvarez.

With dengue, which comes in four closely related serotypes, people who are reinfected with another serotype often develop severe disease.

“It can lead to organ failure and death, it is a major threat to the world, as all four serotypes are now in circulation in most countries,” Velayudhan warned.

He called on countries to promote mosquito control and be “on the alert” to detect the spread of diseases.

“We really want to avoid any major outbreaks.”