Climate change and urbanization are accelerating the spread of dengue in Nepal

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

So far this year, 12 people have died and more than 28,000 have been infected, including 18 in the Solukhumbu region, home to Mount Everest, the world’s highest peak.

Doctors believe the actual number of cases may be higher because not all potentially infected people are tested.

“This shouldn’t be happening here at all,” explains Suman Tiwari, the health director of Solukhumbu district, which is located at an altitude of about 2,500 meters above sea level.

“What is surprising is that some people who had never traveled also tested positive for dengue,” he points out.

In its worst cases, dengue fever causes severe fever, causing bleeding either internally or through the mouth and nose.

The capital Kathmandu, about 1,400 meters away, has reported more than 4,000 cases.

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

“It used to be seen in a certain area, but it is moving towards mountainous areas, even towards the foothills of the Himalayas,” he insists.

In some areas, hospitals are overwhelmed with dengue patients suffering from debilitating fever, body aches and rashes.

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

In October, the UN health agency said the number of reported dengue cases worldwide has roughly doubled every year since 2021, with 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 a “worrying trend.”

Experts say changes in temperature and rainfall patterns caused by climate change and urbanization are creating favorable conditions for Aedes aegypti, the mosquito responsible for transmitting dengue fever.

This means it can survive and reproduce at high altitudes.

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

“When new developments establish a microclimate, the temperature becomes warm and humid,” says Gyawali.

Nepal has seen a dengue outbreak for the third year in a row, appearing to indicate a shift away from cyclical patterns in which outbreaks were expected every two to three years.

The country’s worst outbreak occurred in 2022, with 88 deaths and nearly 55,000 cases, according to government data.

Last year, 20 people died and more than 50,000 cases were reported.

“A cyclical trend was reported earlier, but in recent years it has been observed every year,” says Gokarna Dahal from the Department of Epidemiology and Disease Control of the Ministry of Health.

He also states that it is “injustice” that a developing country like Nepal, which contributes minimally to the burning of fossil fuels that causes global warming, should suffer the more severe impacts of climate change.

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

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

“Part of these efforts must be to combat mosquito-borne diseases such as dengue fever, which are spreading rapidly into new areas,” he adds.

pm/pjm/cwl/mab/zm