CLIMATE CHANGE HELPING DENGUE SPREAD

Dengue fever is a disease closely associated with the environment. Rainfall, temperature and airflow all play a part in assisting transmission.

Ongoing research shows the direct connection between climate change and the spread of dengue fever at higher rates and to previously unaffected communities.

In temperate zones with warmer temperatures, mosquitoes may expand their habitats and are able to live in places they could not previously. 

“The primary factor influencing this situation is temperature, as even a one-degree increase can result in a 10 per cent higher chance of dengue fever occurrences, according to the research we have conducted,” said Kanchana Nakhapakorn, an associate professor with expertise on dengue fever and climate change at Mahidol University.

Nakhapakorn explained that mosquitoes tend to stay inactive and rest when the temperature is lower – below 24 degrees Celsius. But when the temperature rises, they become more active and are able to fly around in search of food.

“If the temperature rises, the developmental process from eggs to larvae and adulthood of mosquitoes accelerates, the chances of them reproducing and spreading increase significantly. This also makes it easier for disease transmission,” she said.

With increasing urbanisation, common throughout Thailand and the Southeast Asia region, reduced airflow in cities means mosquitoes have better conditions to breed.

The onset of the atmospheric phenomenon known as El Nino is also expected to bring elevated temperatures and the likelihood of extreme weather that could exacerbate dengue spread. 

Record heat has already been recorded across many parts of Asia this year and changes to rainfall patterns could prove problematic when trying to contain the disease.

“Since dengue fever occurs due to mosquito bites, improper environmental management could lead to its continuous occurrence. If there is an abnormal amount of rainfall, we surely have reasons to be worried and concerned,” Wisit said.

“When there is frequent rainfall, even small puddles can become breeding grounds for mosquitoes that transmit dengue fever,” he added.