Without timely interventions, dengue deaths could rise significantly by 2030 and further more by 2050, a new paper has warned.
A study led by climate scientists, Sophia Yacob and Roxy Mathew Koll from the Indian Institute of Tropical Meteorology (IITM), Pune, sheds light on the intricate links between climate change and dengue in India.
The paper, published in Nature’s Scientific Reports reveals that a combination of warm temperatures above 27 degrees C, moderate and evenly distributed rainfall, and humidity levels between 60% and 78% during the monsoon season (June–September) increases dengue incidence and deaths. However, heavy rainfall, above 150 mm a week, reduces the dengue prevalence by flushing out the mosquito eggs and larvae, the study, based on data for Pune, found.
“Our findings point to a significant influence of temperature, rainfall, and relative humidity on dengue mortality in Pune, at a time-lag of 2–5 months, providing sufficient lead time for an early warning targeted at curbing dengue outbreaks,” the paper added.
“In a changing climate, dengue-related mortality in Pune is projected to rise by 13% in the near future (2021–2040), 23–40% in the mid-century (2041–2060)... under low-to-high emission pathways in response to the associated increase in temperature and changes in monsoon rainfall patterns,” the paper said.
Though these projections are for Pune, scientists said similar increase can be expected over most of the country. “Without immediate interventions, the combination of rising temperatures and erratic monsoon patterns will not only exacerbate vector-borne diseases like dengue across India but also strain our healthcare systems, leaving vulnerable communities at greater risk,” said Koll, climate scientist, Indian Institute of Tropical Meteorology.
{{/usCountry}}Though these projections are for Pune, scientists said similar increase can be expected over most of the country. “Without immediate interventions, the combination of rising temperatures and erratic monsoon patterns will not only exacerbate vector-borne diseases like dengue across India but also strain our healthcare systems, leaving vulnerable communities at greater risk,” said Koll, climate scientist, Indian Institute of Tropical Meteorology.
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Temperature and humidity over India are projected to increase further in the future, while monsoon rainfall patterns will be getting more erratic. Though heavy rains can wash out mosquito larvae, the model, used by scientists for the paper, shows that the overall increase in warmer days dominates the dengue growth trajectory.
Effective dengue early warning systems rely heavily on comprehensive health data collection and sharing. State public health departments play a crucial role in compiling and disseminating health data. One study indicates that dengue is significantly underreported in India,and claims that the actual number of cases is 282 times higher than the reported figures, Koll said.
“We were able to conduct this study and prepare an early warning system using health data shared by Pune’s health department”, said Koll. “We approached Kerala and other states where dengue cases are high, but health departments there did not cooperate.We have meteorological data readily available from IMD. If health data is shared, we can prepare customized early warning systems for climate sensitive diseases like dengue, malaria, and chikungunya for each city or district in India. Cooperation from health departments is key to saving lives”, Koll emphasized.
States such as Kerala, Maharashtra, West Bengal, Karnataka, Tamil Nadu, Gujarat, Punjab, Haryana, Andhra Pradesh, Telangana, Rajasthan and Uttar Pradesh, which bear a significant dengue burden, can greatly benefit from an advanced early warning system like this to enhance preparedness and reduce the disease’s impact.
“This collaboration highlights the importance of bringing together expertise from diverse fields to address complex climate-health challenges. It is a perfect example of how scientists, the health department, and the government can work together to improve our health warning system,” said Sujata Saunik, Chief Secretary, Govt. of Maharashtra in a statement.
“All predictions are meant for decisions — agriculture, water, health and such. Health applications offer the most stringent tests for weather and climate predictions. We don’t have the luxury of saying there is not enough data. We must use existing data to show what is possible and then identify data gaps to do these much more efficiently and effectively,” said Raghu Murtugudde, climate scientist, University of Maryland and co-author in a statement.