Dengue spreads through Nepal accelerated by climate change and urbanization

Nepal faces a rise in cases of denguea potentially fatal disease unknown in the high-altitude regions of the Himalayas until the emergence of transmitting mosquitoes, due to climate change and urbanization.

In 2004, only one case of dengue was recorded in Nepal. Two decades later, thousands of cases are reported across the country.

Dengue mosquitoes spread from the country’s warm plains to cool valleys and mountainous areas, eventually reaching high-altitude regions.

This year, 12 people died and more than 28,000 were infectedincluding 18 in the Solukhumbu district, where Mount Everest, the highest peak in the world, is located.

Doctors believe the actual number of cases could be higher, as not all potential infections are tested.

“This should not be seen here at all,” explains Suman Tiwari, head of health for the Solukhumbu district, which is located at about 2,500 meters above sea level.

“The surprising thing is that some people with no travel history also tested positive for dengue,” he emphasizes.

In the worst cases, dengue causes intense fevers that cause hemorrhages, either internally or through the mouth and nose.

The capital, Kathmandu, located about 1,400 meters away, recorded more than 4,000 cases.

“Unfortunately it is expanding geographically,” highlights Sher Bahadur Pun, a doctor at the Sukraraj Tropical and Infectious Diseases Hospital in Kathmandu.

“It was previously seen in a certain area, but is moving towards mountainous regions, even to the foot of the Himalayasa”, he insists.

In some districts, hospitals are packed with dengue patients suffering from debilitating fevers, body aches and rashes.

“After each outbreak the number of infected people increases, and my experience is that, after each outbreak, it has become more deadly,” he says.

Injustice

In October the UN health agency said that the number of dengue cases reported globally approximately doubles each year since 2021with more than 12.3 million cases and more than 7,900 deaths reported in the first eight months of 2024 alone.

WHO director Tedros Adhanom Ghebreyesus calls the global spread an “alarming trend.”

Experts point out that Changes in temperature and precipitation patterns, driven by climate change and urbanization, are creating favorable conditions for Aedes aegyptimosquito responsible for transmitting dengue.

This means it can survive and reproduce at higher altitudes.

Narayan Gyawali, a virologist specialized in zoonotic diseases, animal diseases that are transmitted to humans, said that urbanization and the greater mobility of people also drive the increase in dengue cases.

“When microclimates are established in new developments, temperatures become warm and humid,” says Gyawali.

This is the third consecutive year that Nepal has experienced a dengue outbreak, which seems to indicate a change with respect to the cyclical patterns in which outbreaks were expected every two or three years.

The country’s worst outbreak was in 2022, with 88 deaths and almost 55,000 cases, according to government figures.

Last year 20 people died, with more than 50,000 cases.

“Dengue used to be reported in a cyclical trend, but in recent years it is present every year,” says Gokarna Dahal of the Epidemiology and Disease Control Division of the Ministry of Health.

He also states that it is an “injustice” that a developing country like Nepal – which contributes minimally to the burning of fossil fuels that drives global warming – must endure greater impacts of climate change.

Meenakshi Ganguly of Human Rights Watch says that while the primary responsibility for protecting public health lies with Nepal, countries that produce the most global emissions also have an obligation.

“These states must do much more to protect people in countries like Nepal from the consequences of global warming,” emphasizes Ganguly.

“Combating mosquito-borne diseases like dengue, which are spreading rapidly to new areas, must be part of that effort,” he adds.