In temperate Nepal, local weather change paves approach for tropical dengue fever –


  • Nepal is experiencing its worst outbreak of dengue fever in recorded historical past, which well being specialists attribute partially to a altering local weather.
  • Wetter monsoons and hotter temperatures have made for best breeding circumstances for the mosquitoes that carry the virus.
  • Poor water and waste administration are additionally elements, permitting for water to stagnate for lengthy intervals and giving the mosquitoes a spot to put their larvae.
  • Specialists say it should take a mixture of non-public accountability — to eradicate mosquito-breeding grounds — and authorities management — to coordinate the general public well being response — if dengue is to be eradicated in Nepal.

KATHMANDU — Hindus in Nepal marked Tihar this previous week, the pageant of lights that takes place similtaneously the better-known holy day of Deepavali. However for Richa Sharma, a 38-year-old resident of Kathmandu, there was no celebrating; she was bedridden for the previous week.

The mixture of excessive fever, physique aches and burning eyes left her hardly in a position to communicate, she advised Mongabay, “not to mention sleep.”

As of Oct. 21, Sharma was one of many 43,685 individuals (and counting) in Nepal who’ve been identified with dengue fever, transmitted by mosquitoes and also called breakbone illness, due to the muscle spasms and joint pains that it induces. Practically three-fifths, or 25,182, of the instances have been reported within the Kathmandu Valley; 52 individuals have already died as a result of illness.

“Dengue is in every single place in Kathmandu,” stated Rajendra Pokhrel, one other metropolis resident. “It’s like COVID-19. Everybody is aware of at the very least two, three pals or members of the family who’ve been contaminated by the illness.”

Nepal is experiencing its worst dengue outbreak in historical past, in keeping with the World Well being Group. The final large-scale outbreak of the illness was reported in 2019, when 17,992 instances have been recorded nationwide, in keeping with figures from the federal government’s Epidemiology and Illness Management Division. In 2021, there have been simply 540 instances.

For epidemiologists, policymakers, and affected residents, the outbreak has raised a key query: Why is Nepal, a rustic on the foot of the Himalayas, presently within the grip of what’s lengthy been thought of a tropical illness?

Numerous research, a few of them commissioned by the federal government, present that environmental mismanagement, aggravated by local weather change, is responsible for the outbreak of the illness, first reported in a traveler getting back from India in 2004.

The WHO says dengue instances, first reported within the southern plains, the place the circumstances for dengue-bearing Aedes mosquitoes to breed are best, are more and more being reported at larger elevations. It attributes this to elements which will embrace local weather change.

Illness-carrying mosquitoes are extending their distributions to areas that are actually hotter than earlier than, rising the potential for spreading ailments comparable to chikungunya and dengue. Photograph by James Gathany, Public Area.

“The dengue vector [mosquito] requires at the very least 10-12° Celsius [50-53.6° Fahrenheit] to outlive,” stated Meghnath Dhimal, chief environmental well being researcher on the Nepal Well being Analysis Council (NHRC). “As a consequence of local weather change, the variety of chilly nights in winter is declining and the temperature doesn’t fall a lot beneath the 10-12°C mark.

“We’ve got additionally seen that previously, when mosquitoes reached larger altitudes, they’d die,” he added. “However now they’re surviving and breeding even at altitudes of two,100 meters [6,900 feet].”

A 2009 report coordinated by Dhimal and ready by the NHRC and the WHO famous that as inhabitants strain will increase within the nation’s city areas, unplanned settlements broaden with out enough infrastructure associated to the administration of water and strong waste. This, it warned, might set off the unfold of waterborne and vector ailments comparable to dengue.

“The environmental elements triggering the unfold of vector-borne ailments comparable to dengue are primarily associated to water and waste administration, and have lengthy been missed in Nepal’s city areas,” Dhimal stated. “Issues haven’t improved loads because the publication of the report 12 years in the past once we didn’t have a big outbreak of the illness.”

kathmandu aerial view
Kathmandu’s city panorama is unplanned and unregulated. Image By Locus Chand by way of Wikimedia (CC BY-SA 4.0).

As identified by the report, the city poor nonetheless stay in areas with darkish and damp rooms in buildings with leaking pipelines. Many residents are nonetheless pressured to retailer ingesting water in plastic and tin buckets, that are often uncovered, as piped water provides are erratic. These vessels make best breeding grounds for mosquitoes that carry the dengue virus.

Equally, cities throughout Nepal face routine disruptions in strong waste administration, leaving piles of strong waste unattended for lengthy close to human settlements, which then grow to be breeding grounds for mosquitoes.

Along with this, many roads in cities comparable to Kathmandu function insufficient drainage and are notorious for his or her potholes, the place water stays stagnant for a very long time, once more offering refuge for mosquitoes. Damaged-down vehicles parked haphazardly are one other repository of stagnant water.

“So as to add to that, this yr’s pre-monsoon and monsoon seasons have been wetter than regular,” Dhimal stated. “Moist climate has been related to an increment in dengue vector transmission.”

Reshma Tuladhar, affiliate professor of microbiology at Tribhuvan College in Kathmandu, stated that what makes dengue significantly harmful is a phenomenon referred to as antibody-dependent enhancement.

“When an individual is contaminated with dengue, she or he develops antibodies towards the virus,” she stated. “The antibodies assist combat the an infection subsequent time, however provided that the virus is of the identical serotype.”

In Nepal, nonetheless, there are presently 4 totally different dengue serotypes recognized to be circulating. If an individual with antibodies for one in all them is contaminated once more with a virus of a distinct serotype, the antibodies will facilitate the entry of the virus into the cells, fairly than combat them, she stated.

rain nepal street
A street turns right into a stream in the course of the wet season in Kathmandu. Image by Wonderlane by way of Flickr (CC BY 2.0).

Tuladhar stated officers are inclined to deal with mosquito management solely when dengue instances spike. However motion must be taken effectively prematurely, particularly because the temperatures peak in the summertime and the monsoon rains begin, she stated.

Dhimal stated each citizen should take accountability for looking for and destroying mosquito larvae, if dengue is to be eradicated. “We should always not depend on the federal government to come back to our homes and search for mosquito larvae,” he stated. “Every of us ought to try this on our personal.”

However he added the federal government, too, has a key position to play. “Plainly the federal government hasn’t realized from the COVID-19 pandemic,” he stated. “It confirmed that the municipal, provincial and central governments must coordinate efforts to cope with public well being points, particularly associated to sanitation and use of water.”

At her residence in Kathmandu, Sharma stated she hopes to get well quickly and get again to work. “I hope Kathmandu has realized its lesson this yr, and we don’t take the illness evenly,” she stated, “particularly in the course of the subsequent monsoon.”

Banner picture: Individuals queue up for water in Kathmandu, the place a water disaster forces individuals to retailer water in containers that present refuge to dengue-transmitting mosquitoes. Image by Wayan Vota by way of Flickr (CC BY 2.0)


Dhimal, M., Thakur, A. Okay., Shrestha, S. M., Banerjee, M. Okay., & Bhattarai, L. (2009). Environmental circumstances related to vector of dengue and corrective actions for its prevention in Nepal. Nepal Well being Analysis Council. Retrieved from:

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Adaptation To Climate Change, Climate Change, Diseases, Drinking Water, Health, Mosquitoes, Nature And Health, Pandemics, Public Health, Temperatures, Water Crisis



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