As Nepal heats up, a new threat to health threatens: dengue fever

POKHARA, Nepal (Thomson Reuters Foundation) – When Rambhadur Bishwakarma started having a high fever in October, he was not very worried at first.

"I thought the symptoms were simple flu or usual fever," he said. "But things started to deteriorate gradually."

After a week of restlessness, he went to the Fewa City Hospital for a blood test and made an unexpected diagnosis: dengue fever.

"None of our family members had been diagnosed with this disease until now and I had never heard of its incidence in our neighborhood," Bishwakarma said.

However, mosquito-borne dengue fever – generally considered a tropical disease – is gaining ground in the temperate west of Nepal, as climate change is leading to warmer temperatures and changing weather conditions.

Yam Baral, a vector control inspector from the Kaski District Public Health Bureau, including Pokhara, gateway to the Himalayan Annapurna Circuit, said his office had witnessed two cases of dengue in 2017.

This year, there have been more than 150.

"In recent years, the Aedes mosquito has not been able to survive cooler temperatures. But the increase in temperature and rainfall in recent years means that a single infection can cause an epidemic, "warned Baral.

He added that migration of people from tropical areas to the district may have played a role in seeding the disease. But more heat and more rain, in an already wet district, was the reason for its rapid expansion, he added.

Purna Prasad Devkota, head of meteorology at the Lumle Regional Agricultural Research Station, said the average temperature is now rising every year in Kaski.

"Mosquitoes proliferate in districts that have never seen traces of these insects before," Baral said.

Even districts far north of Kaski – including the mountains of Mustang and Manang, which have already experienced snowfall even in summer – are now seeing mosquitoes, he said.

And mosquitoes cause other problems than dengue in Kaski, he added, including cases of malaria and encephalitis.

Last year, the district registered 15 malaria cases, and the number of cases "is expected to increase well beyond that of this year," he said.

The people of Pokhara fear that dengue fever will soon become a recurring problem in the city as cases spread.

"Three of our neighbors have already been diagnosed with the disease and I am afraid we will contract the disease," said Bishnu Parsad Bhandari, owner of a store in Pokhara-8, the most affected part of the district.

"The winter is already here but the mosquitoes are still there," he said.

Sramika Rijal, professor of environmental science at the University of Agriculture and Forestry of the district, attributes responsibility for direct changes to climate change.

"Global warming has helped to expand mosquito habitat, while many cooler areas are warming," she said.

Urban areas such as Pokhara are particularly threatened by the reduced number of mosquito predators, from birds to bats, who live in cities and where people are closer to each other, she said.

The warmer temperatures also increase the frequency with which mosquitoes around the bites, she said.

The district government has launched a series of initiatives to combat the spread of mosquito-borne diseases, ranging from awareness campaigns to efforts to kill mosquito larvae, Baral said.

The district is also trying to speed up the diagnosis of mosquito-borne diseases and closely monitor the number of hospital cases, he said.

But "the number of cases is still on the rise," he said.