Climate change has been associated with the rise in infectious diseases. As the planet warms, fungi are evolving in dangerous ways, threatening our health, food security, and healthcare systems. A study by Norman van Rhijn at the University of Manchester and published on Research Square notes that fungal infections may cause more deaths than malaria annually, but are far less studied and tracked, making them a “silent crisis.”
According to the study, rising global temperatures are enabling fungi to survive at body temperature, making them more likely to infect humans. This adaptation is accelerating due to climate change, leading to the rise of new pathogenic species.
Fungi are among the most abundant organisms on the planet, found in the air, in the soil and inside our bodies, and they can have a significant impact on human health. Moreover, fungi help protect environment, grow food and even develop new medicines.
Despite this, the fungal kingdom is largely unexplored, and according to scientists, less than 10 percent of an estimated 1.5 to 3.8 million fungi species have been described, and only a tiny fraction have had their genetic material (genome) sequenced.
Climate Change and Fungal Adaptation
Research has shown that fungi are resilient and can survive and thrive in places that other organisms cannot, and rising temperatures are causing some fungi to develop the ability to survive higher temperatures.
For instance, Climate change is helping pathogenic fungi to spread to new places. For example, the Coccidioides fungus lives in hot, dry environments, and as more places experience droughts, there are more places where Coccidioides can survive. This fungus causes potentially fatal respiratory infections.
The study also shows that new fungal pathogens are emerging. Candida auris is considered the first new fungal pathogen to emerge due to climate change. It emerged simultaneously on three continents and was ‘born’ resistant to certain antifungal drugs. Candida auris infects people who are already ill and can cause sepsis and multiple organ failure. Candida auris has spread to healthcare environments, where it can grow on plastics in medical equipment.
Fungal colonization of crops can reduce crop yields by a third. And fungi are contaminating food and animal feed, which can lead to illness and death, and as farmers spray crops with the same antifungal drugs used to treat infections in humans, it increases antifungal resistance.
Besides, climate change may help fungi become more drug-resistant. There’s emerging evidence that higher temperatures may help fungi evolve to survive fungicide exposure. As well as aiding the spread of fungal pathogens, climate change may make them more difficult to treat.
The study found that fungal infections can be hard to recognize since their symptoms averlap with other common conditions and healthcare professionals may only realize an infection is fungal when antibacterial drugs don’t work to treat it. Moreover, diagnosis is difficult as there are few effective tests and access is limited.
Researchers claim that developing safe antifungal drugs is extremely challenging, and currently, there are only four classes of antifungal drugs. Similar drugs are used in both agriculture and medicine, giving fungi more opportunities to develop resistance.
Studies indicate that fungal infections among otherwise healthy people are growing. For example, the COVID-19 pandemic saw the spread of Mucormycosis – ‘black fungus’ – in India. This fungus infected recovering Covid-19 patients, attacking body tissues. Severe cases required removal of infected eyes, noses, and jawbones. Some infections were deadly and as climate change spreads pathogenic fungi to new locations more people worldwide will be at risk.
According to Dr. Arturo Casadevall,Chair of Molecular Microbiology and Immunology, Johns Hopkins University, “As the world warms, transposons in soil fungi like Cryptococcus neoformans could become more mobile and increase genomic changes in ways that could enhance virulence and drug resistance. One more thing to worry about with global warming!”
Emerging Solutions
As the threat of fungal infections increases, researchers are seeking new antifungal drugs to protect the population and the food supply chain. This will be reinforced with better regulation around fungicide use to minimize antifungal resistance. Moreover, monitoring and surveillance need to be stepped up to understand the scale of the challenge.
Scientists have proved that fungi have the potential to benefit humans and the ecosystem. For instance, Plant-associated fungi store 13 gigatons of carbon dioxide in the soil, equating to a third of yearly global fossil fuel emissions. Some fungi also help trees and forests to absorb more carbon dioxide, while slowing their rate of return to the atmosphere.
Consequently, understanding more about fungi’s biology could help scientists develop new medicines, make agriculture more sustainable, and improve carbon capture in the journey to net zero.
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