Climate change putting millions more people at risk from infection-causing fungi

• Novel projections show that in 15 years, if we rely on fossil fuels instead of clean power (scenario of SSP585*), we are likely to see the significant spread of certain fungal pathogens in Europe
• Under this scenario, the spread of Aspergillus flavus, for example, could increase by about 16%, putting 1 million more people at risk of infection in Europe. Infections affect the respiratory system, and this fungus infects a broad range of agricultural crops
• The predictions also show that the spread of another fungus, Aspergillus fumigatus, could increase by 77.5% and potentially expose 9 million people in Europe
• This is a concerning trend due to a rise in antifungal resistance and a severe lack of diagnostics and treatment options for fungal infections

In a new study, published on preprint platform Research Square and funded by Wellcome, the effects of rising temperatures on infection-causing fungi have been mapped under different climate change mitigation scenarios until the year 2100. Using climate modelling and forecasts, Dr. Norman van Rhijn at the University of Manchester and colleagues have mapped how the global distributions of three fungal pathogens (Aspergillus flavus, Aspergillus fumigatus and Aspergillus niger) could be expected to change as a result. 

The rise of pathogenic fungi is a real concern and is being driven by climate change. Fungi are incredibly adaptable organisms, with large, malleable genomes that allow them to colonize new geographies and survive as their environment changes. 

Dr. Norman van Rhijn said: “Changes in environmental factors, such as humidity and extreme weather events, will change habitats and drive fungal adaptation and spread. 

“We’ve already seen the emergence of the fungus Candida auris due to rising temperatures, but, until now, we had little information of how other fungi might respond to this change in the environment.  Fungi are relatively under researched compared to viruses and parasites, but these maps show that fungal pathogens will likely impact most areas of the world in the future. Raising awareness and developing effective interventions for fungal pathogens will be essential to mitigate the consequences of this.” 

The maps show that in a fossil fuel dependent economy, as outlined in the IPCC scenario of SSP585, the climate will change to become suitable for fungal pathogens to spread to new geographies, with a marked increase in Europe. 

The spread of Aspergillus flavus could increase by about 16%, putting 1 million more people at risk of infection from this deadly fungal pathogen in Europe. This fungus is known to cause severe infections and is resistant to many antifungals available.

This is an especially concerning trend as many fungal infections have high mortality rates, partly because of the lack of diagnostics, vaccines and treatment options as well as a lack of awareness of fungal infections. Additionally, as fungi are more similar to humans than other pathogens, developing anti-fungal treatments without toxic side effects is challenging. 

The predictions also show that the spread of Aspergillus fumigatus could increase by 77.5% and potentially expose 9 million people in Europe. This is one of the most common fungal pathogens responsible for life-threatening infections in humans and affects the lungs. 

Whilst the rise in global temperatures will increase the spread of fungi in Europe, temperatures in Africa could become so high that some fungi will not be able to survive on the continent. Fungi are an essential component to a functioning ecosystem, decomposing plant and animal matter to reintroduce nutrients into the soil. They also contribute to the carbon cycle which regulates the global climate and temperatures.  

Antifungal resistance is also being driven by the use of fungicides in agriculture, which are used to protect crops and support food production. The researchers also looked at the how the changing environment impacts our use of fungicides.

Viv Goosens, Research Manager at Wellcome said: “Fungal pathogens pose a serious threat to human health by causing infections and disrupting food systems. Climate change will make these risks worse. To address these challenges, we must fill important research gaps. By using models and maps to track the spread of fungi, we can better direct resources and prepare for the future."

Fungal infections are transmitted through fungal spores in the air we breathe. People with weakened immune systems, co-morbidities and other risk factors are most vulnerable to infections, although fungi could adapt to become more pathogenic due to rising temperatures and could result in more infections in healthy people.

Despite this mounting threat, fungal infections receive little attention or resources. Less than 10% of an estimated 1.5 to 3.8 million species have been described, and a tiny fraction has had their genome sequenced. Wellcome is awarding over £50mn in funding towards fungal research over the next year.

-ENDS-

Notes to Editors   

The study has been published on preprint platform Research Square, available here: https://www.researchsquare.com/article/rs-6545782/v1 ; DOI: https://doi.org/10.21203/rs.3.rs-6545782/v1

Shared Socioeconomic Pathways (SSPs) are climate change scenarios of projected socioeconomic global changes up to 2100 as defined in the IPCC Sixth Assessment Report on climate change in 2021. They are used to derive greenhouse gas emissions scenarios with different climate policies.

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