Because the Indian capital is teeming with mosquitoes

The Delhi wave The Culex mosquitoes come at a time when public health officials are declaring remarkable victories against other types of mosquitoes, including the malaria-transmitting genus Anopheles. Although these gains have saved lives, the situation, mosquito experts say, is complicated: the same changes that have reduced the numbers of Anopheles could allow other species to thrive. And in a changing climate, mosquitoes have found new niches to exploit, especially in urban areas.

In recent decades, global malaria footprints have declined, in part thanks to interventions such as mosquito nets and insecticides used to target Anopheles. In India, these interventions were implemented with the help of a government agency called the National Center for Vector Borne Diseases Control. The program’s efforts have helped to drastically reduce deaths from malaria in recent years.

A retired government official who worked in northeastern India at the ICMR for nearly three decades, Vas Dev, said deforestation likely contributed to the decline in malaria rates in India, but it came at a cost. . Increased urbanization creates more habitats for mosquitoes that prefer urban and suburban landscapes, including Culex and Aedes, the genus of mosquitoes that transmit dengue, Zika, and chikungunya. Since the 1970s, dengue has spread dramatically in poor countries, killing thousands of people every year, mostly children.

Scientists are working to better understand how changing landscapes and climate will affect mosquito populations in the future. In Delhi, climate change has already extended the breeding season by bringing higher temperatures to months that were once too cold for breeding. The premature rains have also fed the mosquito population by increasing humidity levels and contributing to the stagnation of water in the environment. As a result, Dhiman said, areas that could once have experienced a month-long mosquito season are now experiencing seasons that span six to eight months.

Insects are known to adapt quickly to changes in their local environment. Anopheles mosquitoes provide an interesting example, said Karthikeyan Chandrasegaran, a postdoctoral researcher at Virginia Tech who has experience in evolutionary ecology and mosquito biology. The malaria-transmitting insect is known to bite between dusk and dawn, so public health organizations working in sub-Saharan Africa have invested in mosquito nets for local residents. Initially, these interventions proved effective, but cases have increased in less than a decade. It turned out that the mosquitoes were feeding early in the morning after people got out of bed. Mosquitoes can also develop resistance to commonly used insecticides.

City dwellers are likely to bear the brunt of any problems, Chandrasegaran said. Poor waste management, lack of sanitation and irrigation create opportunities for insect growth. Some cities, such as Delhi, are also struggling with water shortages, a situation that has led residents to accumulate scarce supplies in buckets that can become breeding sites. These conditions are less acute in rural areas, which are also home to more mosquito predators, including some fish and frogs.

But rural areas also present challenges, including limited health infrastructure and low awareness of vector-borne diseases. “So, you will probably have to adapt your solution differently to urban areas, to adapt your solution differently to suburban areas, rural areas, wooded areas,” Chandrasegaran said. “If you don’t identify the weaknesses exactly, you will spend a lot of time, effort and money trying to implement a scheme across the country, which will waste a lot of things.”

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