In the TV series, The Last of Us, a mutant fungus spreads rapidly among humans, turning them into zombies.
The show is, unsurprisingly, science fiction. However, a new study from researchers at The University of Manchester has found that the risk of fungal infection in Europe has increased — and climate change is a significant factor.
The study found that the aspergillus species - which can cause fatal human brain infections, destroy livestock and make crops unsafe to eat - is forecast to spread through Europe into the UK.
Fungal infections are transmitted via fungal spores in the air we breathe. They are usually resolved with antifungal treatment, but people with weakened immune systems are at particular risk of serious harm.
What is the new fungal threat and how worried should we be?
What did the study find?
The study found that if we are more reliant on fossil fuels than clean power, it’s likely that there will be a significant spread of three fungal pathogens: Aspergillus flavus, Aspergillus fumigatus and Aspergillus niger.
“Changes in environmental factors, such as humidity and extreme weather events, will change habitats and drive fungal adaptation and spread,” said Dr. Norman van Rhijn, research fellow in microbial evolution and lead author of the study.
The Aspergillus species is forecast to spread from Africa and South America into Europe and Asia.
“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.”
Invasive fungal infections are not new. There are more than 200 fungal species known to cause disease in humans, causing an estimated 2.5 million deaths every year.
However, the study found that Aspergillus flavus, a common soil fungus, could increase by approximately 16 per cent, leaving 1 million more people in Europe at risk of infection.
Aspergillus flavus infections impact the respiratory system and can infect a variety of crops. It is resistant to many antifungals available.
Aspergillus fumigatus, one of the most common fungal pathogens, could increase by 77.5 per cent, causing 9 million people in Europe to be exposed.
The treatment-resistant pathogen affects the lungs and is responsible for life-threatening infections in humans. People infected with it are “33 per cent more likely to die,” according to U.S. Centers for Disease Control.
What is Aspergillus?
Aspergillus is a common mold that can cause an infection called Aspergillosis when inhaled.
The infection is rare in healthy people but can cause mild to severe illness in certain groups, such as people with a weakened immune system or lung disease.
Aspergillosis symptoms
- Coughing
- Shortness of breath
- Nasal congestion
- Headache
- Fatigue
- Coughing up blood
There are about 180 species of Aspergillus but fewer than 40 are known to cause infections in humans.
How likely is a fungal pandemic?
Fungal infections can be particularly concerning because they are often harder to treat.
In 2022, the World Health Organisation report listed 19 fungi that were a danger to public health, flagging that a historic lack of focus on fungal infections had resulted in significant gaps in knowledge on treatments and diagnostics.
While there are more deaths associated with bacterial superbugs than fungi (4.7 million verses 3.8 million), there are only 17 available antifungal drugs compared with hundreds of antibiotics for bacterial infection, according to the US Centers of Disease Control and Prevention (CDC)
This is partially because it’s difficult to kill fungus without causing harm to humans at the same time.
“Genetically, fungi are more closely related to humans than they are to bacteria,” infectious disease specialist Dr. Neil Clancy, an associate professor of medicine and director of the mycology program at the University of Pittsburgh, told CNN.
“If you’re trying to make an antifungal drug, you’ve got to come up with targets that won’t harm genes and proteins humans have.
“Right now, the drug we use that kills fungus best cross-reacts with human kidney cells, so you can end up with kidney failure.”
So could a spike in fungal infections amount to a pandemic?
“A pandemic as we have seen with COVID-19 is unlikely,” Norman van Rhijn told The Standard, emphasising the unlikelihood that Aspergillus would infect someone who has a ‘normal’ immune system.
However, he said that there is “a broad range of predisposing factors” for fungal infection, spanning everything from asthma to being a heavy smoker.
“Over the last couple of years, we appreciated that even things like severe influenza and COVID actually are a predisposing factor for developing a fungal infection.”
As well as this, he warns that “nature and evolution can be unpredictable so there is a very small chance that fungi evolve to bypass our immune system.”
How can you protect yourself from Aspergillosis?
“To protect yourself from fungal infections caused by Aspergillus, one must avoid areas with high levels of dust and mould,” Dr Bruno Silvester Lopes, lecturer in Microbiology at Teesside University, told The Standard. Areas such as construction sites, compost piles with decaying organic matter, piles of leaves and grain storage areas should be avoided.
He added that “wearing an N95 mask in dusty areas and using protective measures while gardening can also reduce the risk of exposure.”
At home, it’s essential to have good ventilation and use a dehumidifier where possible, to keep the humidity below 50% inside.
“Some species of Aspergillus, such as Aspergillus flavus and Aspergillusniger, are common foodborne pathogens and can produce toxins. Hence, foods such as grains, nuts, and spices must be stored in a cool, dry place,” he said.
“For individuals with low immune status, routine screening can be considered if the risk for pulmonary or invasive aspergillosis is very high.”
