A fungus that "devours" humans from the inside out may spread as global temperatures rise

Dubai, United Arab Emirates - New research predicts that the infectious fungus responsible for millions of deaths annually will expand dramatically and reach new areas as the planet warms. Fungi are ubiquitous, playing an important role in ecosystems, but they can pose a devastating threat to human health, with fungal infections killing an estimated 2.5 million people annually.

The lack of data means that this number may be much higher, especially since these organisms have a superior ability to adapt to rising temperatures. A team of scientists from the University of Manchester in the UK used computer simulations and predictions to map the potential future spread of Aspergillus, a common group of fungi spreading around the world.

It can cause aspergillosis, a life-threatening disease that mainly affects the lungs. The team found that the range of some Aspergillus species will expand as the climate crisis worsens, extending into new parts of North America, Europe, China and Russia.

The study published in May is currently undergoing peer review. One of the study's authors, climate change and infectious disease researcher at the University of Manchester, Norman van Rijn, said: "Fungals are less researched than viruses and parasites, but these maps show that fungal pathogens will likely affect the majority of the world in the future."

Aspergillus grows as tiny threads in soil all over the world, releasing huge numbers of tiny spores that spread through the air like most fungi. Humans inhale spores every day, but most people do not suffer from any health problems because their immune systems work to eliminate them.

The situation is different for people with lung diseases, including asthma, cystic fibrosis, and chronic obstructive pulmonary disease, as well as for people with weakened immune systems, such as cancer patients, those who have undergone an organ transplant, or have had severe influenza or the “Covid-19” virus. If the body's immune system fails to eliminate the spores, the fungus "starts to grow and eat the body from the inside out," Van Rijn said.

Aspergillosis has a very high mortality rate of between 20% and 40%, and is difficult to diagnose, as patients often suffer from symptoms common to many diseases, such as fever and cough. Van Rijn added that fungal pathogens are becoming more resistant to treatment, and only four types of antifungal drugs are available.

The study found that the flavus type of Aspergillus fungus, which prefers hot, tropical climates, could see its spread increase by 16% if humans continue to burn large amounts of fossil fuels. It is expected to spread to parts of North America, northern China, and Russia.

This species, which is resistant to many antifungal drugs, can cause severe infections in humans. This fungus also infects a range of food crops, posing a potential threat to food security.

The World Health Organization (WHO) has included the flavus species on the list of critical fungal pathogens in 2022 due to its public health impact and risk associated with antibiotic resistance. The Aspergillus fumigatus species, which prefers milder climates, is expected to spread northward toward the Arctic as global temperatures rise.

The study found that its prevalence could increase by 77.5% by 2100, which could put 9 million people in Europe at risk. Conversely, in some regions, including sub-Saharan Africa, temperatures may become too high to be suitable for Aspergillus fungi.

This could lead to a different kind of problem, as fungi play an important role in ecosystems, especially in maintaining healthy soil. In addition to expanding their growth range, rising global temperatures may also increase the ability of fungi to tolerate temperatures, which may enable them to better survive inside human bodies.

The new study "really highlights the threat that fungi pose to our natural environment, and how ill-equipped we are to deal with changes in their pattern of spread," said Elaine Bignell, co-director of the MRC Center for Medical Mycology at the University of Exeter in the UK, who was not involved in the research. But many uncertainties remain, and there is still a huge amount of research to be done.

A professor of environmental health sciences at the University of California, Berkeley, who was not involved in the research, explained that despite the deadly nature of aspergillosis, there is a real lack of data regarding where the pathogens of this disease are found in the environment and who is most at risk of contracting it.