Nepal’s dengue outbreak exposes climate risk

Nepal saw its biggest and longest dengue outbreak this monsoon so much so that there are still cases being reported into winter. As of 20 November, 60 people have died of dengue while 52,557 cases have been reported.

The surge also pointed towards vector insects like mosquitoes moving up the Himalaya, with increasing temperatures, and in turn spreading infectious diseases across the region. In the past there have been incidences of malaria and kala azar in high mountain villages of Nepal.

Dengue and other mosquito-borne diseases are projected to become more widespread and severe in Nepal as a result of warming temperatures linked to climate change. Now, the Human Rights Watch has urged Nepali authorities to bolster public health systems that struggled during a dengue fever outbreak in recent months.

Read also: ‘Like a sunburn on your lungs’: how does the climate crisis impact health?, Emily Holden

“As temperatures are rising, the federal government and local governments need to work together to protect people from the growing threat posed by outbreaks of diseases,” says Meenakshi Ganguly, South Asia director at Human Rights Watch. “The governments of countries that have been most responsible for the emissions that are driving climate change should support Nepali efforts, including access to vaccines.”

According to the Intergovernmental Panel on Climate Change (IPCC), the world’s leading authority on climate science, “at high elevations in Nepal, there is high confidence that climate change has driven the expansion of vector-borne diseases that infect humans.”

Wealthy countries, whose greenhouse gas emissions are mainly responsible for climate change, should live up to their climate finance commitments and do more to support Nepal in responding to climate-based disasters, Human Rights Watch stated further.

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The Himalaya is warming 0.3 to 0.7oC faster than the global average. At this rate, two-thirds of Himalayan glaciers will be gone, affecting 1.9 billion people living downstream. The panel also warned that “viruses like dengue, chikungunya, and Japanese encephalitis are emerging in Nepal in hilly and mountainous areas.”

Dengue is a mosquito-borne virus that can cause a range of symptoms including high fever, nausea and vomiting, aches and pains of muscle, joint, bone or eyes. In critical cases, patients need to be hospitalised and require urgent platelet transfusion.

Unlike in other infectious diseases, people reinfected with dengue with a different strain can develop severe complications which have specialists believing that Nepal is vulnerable to even more serious outbreaks in the near future. Doctors also fear that the Zika virus, which can cause infants to be born with microcephaly and serious neurological complications, could be spread in the future by the same mosquitos.

Like dengue, Zika is transmitted predominantly through the bite of an infected Aedes aegypti mosquito. The virus can also be transmitted during pregnancy to the fetus and through unprotected sex. Infected people are often asymptomatic or experience mild symptoms: fever, muscle and joint pain, conjunctivitis, and rash. Zika has been detected in 89 countries and territories, and has been declared a global public health emergency by the WHO.

Read also:  Climate-health emergency, Sonia Awale

Nepal has had annual dengue outbreaks since 2006 when it was first detected on a foreigner. 2019 saw the last largest outbreak with almost 18,000 recorded cases. The 2022 outbreak, almost three times as large, also recorded cases over a longer season. In previous years dengue cases were found at lower altitudes, but in 2022 it has spread to at least 76 of Nepal’s 77 districts, including high altitude regions.

“This is related to climate change, because the rate of warming is much greater at higher altitudes,” says Megnath Dhimal, a government public health expert and contributor to the IPCC report. “We need to enhance our infrastructure and capacity for future outbreaks. The most climate-vulnerable countries are developing countries like Nepal.”

But the true number of infections is likely to be several times higher than the official statistics, as some 90% of dengue patients are asymptomatic. Urban environments are particularly susceptible to dengue outbreaks, according to the WHO, because the mosquitoes carrying it breed “mostly in man-made containers including buckets, mud pots, discarded containers, used tyres and storm water drains.” The mosquitos fly around 500m in their lifetime, and as such are more dangerous in densely populated areas.

There is no medication for dengue: doctors can only treat and manage its symptoms. Thus, controlling mosquitoes by destroying their breeding sites is the next best option. Although municipalities in Kathmandu came together for a search, locate and destroy operation, the response was too little too late.

Read also: The dangers of the dengue virus, Tom Robertson

The Nepal government has developed a National Adaptation Plan 2021-2050 to respond to climate change, which envisages spending $500 million to strengthen preparedness and responses to climate sensitive diseases by 2030. But coordination and implementation between different levels of the government remain challenging. Experts say international health agencies have also not delivered effective support.

“Ad hoc activities to combat dengue are implemented, but very few effective interventions,” says Keshab Deuba, an infectious disease epidemiologist. “Very few activities are happening at the community level that would control these cases.”

Meanwhile, Nepal’s weak health infrastructure means there have been preventable deaths due to lack of timely access to healthcare. Kathmandu where the epidemic was concentrated, Nepal’s only hospital specialising in tropical diseases was stretched to its limit.

“The quality of the available health service is very poor, and in remote areas it is almost non-existent,” adds Deuba. “We are not able to manage cases and prevent deaths.”

Nepal’s Constitution guarantees the right to basic health care services to its people. The country just held its general elections on 20 November, and the new federal, provincial and local governments should work together to strengthen and coordinate systems to control and treat outbreaks.

“Without effective measures to remove breeding grounds, reduce transmission, and improve treatment, Nepal is likely to suffer much worse outbreaks of dengue and other mosquito-borne diseases as temperatures rise in the coming years,” wards Ganguly. “If the government fails to act to protect people’s right to health, the health of millions of Nepalis may be placed in jeopardy.”

Read more:

Mosquitoes move up mountains as the earth warms, Sonia Awale

The Third Pole is warming faster than expected, Kunda Dixit