Dengue cases surge in South Asia amid global warming, unchecked urbanisation

NEW DELHI: Ms Bimla’s family of 11 have all contracted dengue fever at some point in the last few years.
Her relatives even moved out due to the unsanitary conditions of their neighbourhood in New Delhi.
An open drain running along it is clogged with garbage, sewage and stagnant water – the perfect breeding ground for the Aedes aegypti mosquito, which carries the dengue virus.
“My daughter-in-law is not able to walk since she fell ill last year. Her knees are still inflamed and she’s still weak,” Ms Bimla told CNA.
“Her daughter is also recovering. It takes more than six to seven months once you fall sick to get back on your feet.”
Ms Bimla’s granddaughter even caught the illness in February, when it should technically be too cold for the mosquito to breed.
What used to be a viral disease limited to the monsoon months has now become a year-round problem, with some experts warning that dengue could become a global pandemic threat.
Dengue has no known cure or treatment. It is also called “breakbone fever” because of the severe muscle and joint pains that occur during infection, as well as high fever.
Dengue cases in India have been steadily rising since 2020. The number of cases in the first half of 2024 – more than 32,000 – are nearly double of what was reported in the same period last year.
The country recorded almost 290,000 cases last year – 50,000 more than the year before.
A rise in infections on the subcontinent has been driven by the ongoing monsoon season, which typically lasts from June to September. Cases have similarly been reported throughout the year in far higher numbers in countries like Nepal, Bangladesh and Sri Lanka.
Experts said global warming – which has led to an extended monsoon season and higher humidity levels – is to blame.
The tropical weather, coupled with widespread waterlogging during the monsoon season, gives the Aedes mosquito perfect conditions to thrive.
Some also pointed to rapid and unchecked urbanisation in South Asia.
Thousands live in densely populated enclaves without proper water supply, sanitation, or waste management systems. Stagnant water that often collects in the streets also make optimum breeding grounds for mosquitoes.
Urban designer Adarsha Kapoor suggested ensuring a steady supply of piped water, so residents do not need to store water in cans and jars. Areas that are prone to waterlogging could also be improved through maintenance, he added.
But Ms Bimla said these are long-term measures that do not immediately solve the problems that she and her neighbours face.
They want officials to ensure the drains are covered and anti-dengue measures are taken throughout the year – not just when cases rise.
Nevertheless, anti-dengue drives have begun in some parts of New Delhi.
Officials are spraying insecticides into open drains to kill mosquito larvae, using a dense white fog of chemicals to fumigate mosquito-breeding hotspots.
They are also trying to spread awareness among residents with the message: Cover it up.
“The most common way mosquitoes breed is in water containers at homes,” said Dr Parul Jain, zonal entomologist from the Municipal Corporation of Delhi.
“In homes where there is no running water, there can be 10 to 12 containers. Some residents do keep these covered, but not everyone does.
“The only way this disease spreads is if mosquitoes breed, and once they do breed, very quickly there can be a cluster of infections,” he added.