Climate Change Is Fueling The Spread Of Dengue Across New Regions

Dengue is no longer just a monsoon-season illness confined to tropical regions.

Across India and many parts of the world, outbreaks are beginning earlier, lasting longer and appearing in areas that previously reported few or no cases. Health experts say climate change is emerging as a key factor behind this shift.

According to Dr. Harshad Limaye, Director of Infectious Diseases and Internal Medicine at Nanavati Max Super Speciality Hospital, changing weather patterns are creating conditions that allow dengue-carrying mosquitoes to thrive for longer periods and in a wider range of locations.

“Dengue is no longer behaving like a strictly seasonal or limited tropical infection. Across many regions, doctors and public health teams are seeing dengue appear earlier, last longer, and reach areas where it was once uncommon. One major reason for this shift is climate change,” he said.

Why Climate Change Is Influencing Dengue

Dengue is caused by a virus transmitted by infected Aedes mosquitoes, which breed in clean stagnant water commonly found in coolers, flowerpots, tyres, water tanks, construction sites and uncovered containers.

As temperatures continue to rise and rainfall patterns become increasingly erratic, the environment is becoming more favourable for mosquito breeding and virus transmission.

“These mosquitoes thrive in warm, humid environments. As temperatures rise and rainfall patterns become more unpredictable, the conditions around us are becoming more suitable for mosquito breeding and virus spread,” Dr. Limaye explained.

Rising Temperatures Speed Up Transmission

Warmer weather can accelerate dengue transmission in several ways. Mosquitoes develop more quickly in higher temperatures, bite more frequently and often survive longer. At the same time, the dengue virus matures faster inside the mosquito, shortening the time needed before it can infect humans.

“This means that during favourable weather, dengue transmission can become faster and outbreaks can grow more quickly,” Dr. Limaye said.

Unpredictable Rainfall Creates Breeding Grounds

While dengue has traditionally been associated with the monsoon season, changing rainfall patterns are making outbreaks less predictable.

Heavy rainfall and flooding often leave behind pools of stagnant water that become ideal breeding sites for mosquitoes. However, drought conditions can also contribute to dengue risk, as people tend to store water in containers that may become mosquito habitats if not properly covered.

“Droughts can increase dengue risk because families may store water in containers, which can become mosquito breeding sites if left uncovered,” Dr. Limaye noted.

Dengue Expanding Into New Regions

Climate change is also widening the geographical footprint of dengue. Rising temperatures are allowing Aedes mosquitoes to survive in areas that were once considered too cool, including some higher-altitude and temperate regions.

As a result, communities with little previous exposure to dengue may now face an increased risk of outbreaks. Although extremely high temperatures can reduce mosquito survival in certain locations, experts believe the overall trend points toward a broader expansion of dengue-prone areas.

Urbanisation Adds To The Challenge

Climate change is not the only factor driving dengue’s spread. Rapid urbanisation is creating additional opportunities for mosquito breeding.

Poor drainage systems, waterlogging, construction activity, waste accumulation and irregular water supply in densely populated cities provide ideal conditions for mosquito growth. Increased travel and movement of people can then help spread the virus between regions.

“Human travel and daily movement can carry the virus from one area to another, allowing outbreaks to spread beyond their original location,” Dr. Limaye said.

How To Reduce Your Risk

Experts recommend taking preventive measures throughout the year rather than waiting for dengue season to begin. Key steps include:

Removing stagnant water from homes and surroundings regularly
Covering all water storage containers
Cleaning coolers, drains and water tanks frequently
Disposing of old tyres, bottles and unused containers properly
Using mosquito repellents
Wearing full-sleeved clothing, especially during the daytime

Unlike many mosquito species, Aedes mosquitoes are most active during daylight hours, making daytime protection particularly important.

Symptoms That Need Medical Attention

Seek medical advice if a fever is accompanied by:

Severe headache
Pain behind the eyes
Body and joint aches
Skin rash
Vomiting
Abdominal pain
Bleeding from the nose or gums
Drowsiness
Sudden weakness

Early diagnosis and treatment can significantly reduce the risk of severe complications.

Experts say climate change is reshaping dengue transmission by extending mosquito breeding seasons, altering rainfall patterns and enabling the disease to spread into new areas. While addressing climate change requires long-term global efforts, simple preventive actions at the community level remain one of the most effective ways to curb dengue transmission.

“Climate change may be a large global challenge, but dengue prevention still begins with small, consistent action around our homes and neighbourhoods,” Dr. Limaye said.