Global Dengue Risk in 2013 (Image: Jane Messina/UCANR)Global Dengue Risk in 2013 (Image: Jane Messina/UCANR)

Dengue on the rise (in Nepal, and worldwide). Blame ‘migration’ and ‘climate change’

Dengue is on the rise – in Nepal, and across the globe, at an earlier un-witnessed rate. First recorded dengue in the 1950s during dengue epidemics in the Philippines and Thailand, by 2010, the number had jumped to 2.2 million cases. An estimated 3 billion people from more than a hundred countries are said to be at ‘risk of contacting the disease’.

The disease, a mosquito-borne viral disease is transmitted by female mosquitoes mainly of the of the species Aedes aegypti and, to a lesser extent, Ae. albopictus. This mosquito also transmits chikungunya, yellow fever and Zika infection – its spread in Nepal in 2019 is alarming. Dengue spreading mosquitoes live in urban habitats and breed mostly in man-made containers. Although a minimal percentage of the total mosquito population transmit the disease, its growth is contributed to ‘human migration’ and ‘climate change’.

In Nepal, two people died of dengue, one from Chitwan District and one from Doti. While dengue in Chitwan is heard of (225 people out of 567 tested positive within the last month alone, that too most within the metropolis region), the incident in Doti is first.

Doti is a hilly district, where dengue is largely unheard of. Therefore, when Chatra Malaski (42) was bed-ridden of high-fever, the family assumed it was viral fever like everyone else’s. However, when the fever ran unabated, they brought her down to Maya Metro Hospital, Dhangadhi. However, it was too late, and she passed. Doctors could not believe she had ‘dengue’ – Chatra Malaski had never been out of the district.

Similarly, the dengue spreading mosquitoes have spread to several countries – its spread to new regions is mostly said to be owing to human migration – for example the mosquitoes are said to have made their way to Europe and North America via several sources, luggage of travellers’ a primary mode of transport. Eggs attached to used tyres and lucky bamboo also contributed towards their growth.

While climate change does not directly contribute towards their growth, the warmer climate provides favourable conditions for them to live, and thrive.

Look at Doti – human activity is increasing, the climate is warming, and mosquitoes have made their way in.

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