The influence of heatwaves fuelled by climate change and cold snaps on the spread of diseases is likely to have been underestimated using current prediction methods, Irish scientists have found.
Researchers at Trinity College Dublin have shown differences in heatwaves – such as how much hotter they are than normal temperatures and how long they last – “can increase or decrease disease burden by up to 13 times, when it comes to parasites infecting humans”.
Their discovery coincides with climate change and related extreme weather events impacting across the planet and predicted to get worse.
“Given the increased frequency and intensity of heatwaves in particular, it’s crucial to understand how these events will affect the spread of disease,” said postgraduate researcher at TCD School of Natural Sciences, Niamh McCartan, lead author of a study published in PLOS Climate on Wednesday.
Five of the best family friendly hiking trails around Ireland: From easy to demanding
Seen & heard: Irish drivers turn away from Elon Musk’s Tesla in favour of Chinese rival
Child (7) dies after suffering ‘sudden heart condition’ on bouncy castle
Tony Holohan ‘full of joy’ as he shares news of marriage to Ciara Cronin
[ Commitment to climate action hard to find in GovernmentOpens in new window ]
While scientists have a relatively good idea of how temperature impacts some viruses and disease-causing pathogens and parasites, they know much less about the effects of sudden heatwaves or cold snaps, or how influential variation in duration of these events are, she said.
“Climate change is also causing mosquito species that carry diseases like dengue, Zika, and malaria to be increasingly found in parts of southern and central Europe, including Italy and France, areas that were previously too cool to support them,” she said .
“While Ireland has so far been less affected, the findings of our study highlight the urgent need to understand how warming and extreme weather events can alter disease dynamics more broadly.”
They worked with the water flea and a tiny “microsporidian pathogen” that are used widely to predict environmentally transmitted diseases. “This approach gave us 64 unique heatwaves for comparison.”
A recently published study reported “58 per cent of human pathogenic diseases have been aggravated by climate change, with temperature changes impacting host susceptibility due to altering biological properties such as how our immune systems function, as well as our behaviour”, Ms McCartan said.
Overly simplified models “may miss critical complexities”, she said. “Future disease-specific models must account for fluctuating and extreme temperatures, not just averages.”
Other research has suggested almost 70 per cent of Covid-19 cases in the summer of 2022 could have been avoided if there had not been heatwaves around that time. “Imagine the difference that a better understanding of how heatwaves alter disease dynamics could have made to countless people,” she said.
