Is climate change extending dengue’s reach?

Playing into the hands of mosquitoes…

Climate change could be helping dengue spread in several ways.^1-4 Dengue transmission can increase as warmer and more humid climates than before promote the growth and development of disease-carrying mosquitoes.^1-4 Also, changes in rainfall can mean more standing water for mosquitoes to breed in.²

Rising temperatures help mosquitoes thrive and survive

Warmer temperatures lead to higher numbers of dengue-carrying mosquitoes (known as Aedes mosquitoes) by increasing their survival and growth rates. What’s more, warmer temperatures may cut the time it takes for the dengue virus to develop and become infectious when it’s inside the mosquito.^3–5 

These factors may be contributing to the sharp increase in dengue cases, and as the global climate warms further, the number of places affected by dengue is expected to grow.⁶

Rising rainfall means rising reproduction rates

Climate change can lead to heavier rainfall as warmer air can hold more water.⁷ Rising rainfall can also mean more dengue, as puddles, ponds, or other bodies of water provide places for the mosquitoes to lay eggs and multiply. A peak in dengue cases has been seen to occur 2 months after peak rainfall.^4,8

Higher humidity helps mosquitoes survive

Humidity increases the activity and survival rates of mosquitoes. The net result of this is higher daily biting rates, mosquito dispersal and egg laying.^9,10 

Climate change means that dengue is now a threat in areas which it previously wasn’t.^3,9 This makes it vital to maintain up-to-date knowledge of the new areas in which dengue may now be a risk and the steps needed to minimise this threat.