Aspergillus, a fungus likened to the deadly organism in “The Last of Us” for its destructive potential, is spreading to new regions due to global warming, according to a May 2025 study from the University of Manchester. Using climate simulations, the research predicts that species like Aspergillus flavus and fumigatus, which cause aspergillosis—a lung infection with 20% to 40% mortality rates—will colonize parts of North America, Europe, China, and Russia by 2100. Rising temperatures favor these fungi, which also infect crops, threatening food security. Vulnerable groups, such as those with weakened immune systems or conditions like asthma, face the highest risks. The World Health Organization (WHO) lists Aspergillus as a critical pathogen, but limited treatments and diagnostics raise concerns. Extreme weather events, like floods, further amplify the spread of fungal spores.
Found in soil, water, and air, Aspergillus releases microscopic spores inhaled daily. Healthy individuals typically clear these spores, but those with conditions like cystic fibrosis or severe Covid-19 are at risk.
Aspergillosis is often misdiagnosed due to common symptoms like cough and fever, contributing to its high mortality.
- Key species: Aspergillus flavus and fumigatus, resistant to antifungals.
- Affected regions: North America, Europe, China, Russia.
- Agricultural threat: Impacts crops like corn, wheat, and rice.
Climate-driven fungal expansion
Global warming creates ideal conditions for Aspergillus proliferation. The University of Manchester study projects that Aspergillus flavus, suited to tropical climates, could expand its range by 16% under high-emission scenarios. Areas like the southern U.S. and northern China, previously less hospitable, are becoming suitable habitats.
Aspergillus fumigatus, thriving in temperate climates, is expected to shift northward into northern Europe, with a projected 77.5% range increase by 2100, potentially exposing 9 million Europeans to infection risks.
In contrast, extreme heat in regions like Sub-Saharan Africa may reduce fungal presence, disrupting ecosystems where Aspergillus aids soil health.
- Climate factors: Rising temperatures and extreme weather like droughts and floods.
- Projected impact: 16% expansion for flavus, 77.5% for fumigatus.
- Less affected areas: Sub-Saharan Africa due to excessive heat.
Global health risks
Aspergillosis claims approximately 2.5 million lives annually, based on global estimates. Its resistance to antifungals, with only four drug classes available, complicates treatment. A UC Berkeley study identified over 20,000 cases in the U.S. from 2013 to 2023, with a 5% annual increase.
Immunocompromised patients, such as those with cancer or transplants, and those with chronic lung diseases like COPD, are most vulnerable. Diagnostic challenges, due to symptoms mimicking other respiratory conditions, exacerbate the issue.
Agricultural impact
Aspergillus flavus infects staple crops like corn, rice, and peanuts, causing up to 30% yield losses in tropical regions. Its spread to new agricultural zones, such as Russia and northern China, threatens global food security.
The fungus’s resistance to agricultural fungicides limits control options, particularly in grain-exporting countries. The WHO warns that agricultural impacts could worsen hunger in vulnerable regions.
- Affected crops: Corn, wheat, rice, peanuts.
- Estimated losses: Up to 30% in tropical areas.
- Control challenges: Resistance to fungicides.
Role of extreme weather
Extreme weather events, increasingly frequent due to climate change, facilitate Aspergillus spore dispersal. A 2011 tornado in Joplin, Missouri, triggered an aspergillosis outbreak, with 13 cases and five deaths. Floods create humid conditions ideal for fungal growth, while droughts release accumulated spores.
These events heighten exposure risks in urban and rural areas, particularly in regions unprepared for fungal outbreaks.
Fungal heat tolerance
Rising global temperatures enhance Aspergillus’s heat tolerance, enabling it to survive better in the human body at 37°C. Aspergillus fumigatus is adapting to warmer climates, increasing its infection potential.
Studies suggest a 1°C global temperature rise could double the fungus’s ability to colonize new environments, raising risks in tropical regions.
- Thermal adaptation: Survival at human body temperatures.
- Risk increase: Doubled colonization with 1°C rise.
- Implications: Harder-to-treat infections.
Research gaps
Fungal pathogens receive less research attention than viruses or bacteria. In Europe, under 10% of aspergillosis cases are accurately recorded, and U.S. data from UC Berkeley indicate widespread underreporting. Limited environmental data on Aspergillus distribution hinders prevention efforts.
The WHO, which added Aspergillus to its critical pathogen list in 2022, calls for increased investment in surveillance and antifungal development. Lack of equipped labs in many regions compounds the problem.
“The Last of Us” spotlight
The HBO series “The Last of Us,” depicting a mutant fungus turning humans into aggressive creatures, has raised awareness of fungal threats. While fictional, the show highlights real dangers of pathogens like Aspergillus, according to researchers like Norman van Rijn.
Despite public interest, funding for fungal research remains low, with only 1.5% of global health resources allocated to fungal infections. The series has sparked discussions on global preparedness.
- TV series: “The Last of Us” emphasizes fungal risks.
- Funding: 1.5% of health resources for fungi.
- Cultural effect: Increased public awareness.
Vulnerable populations
Elderly individuals over 65, accounting for 40% of U.S. aspergillosis cases, are highly susceptible due to chronic conditions. Children with cystic fibrosis and patients undergoing chemotherapy also face elevated risks.
UC Berkeley data highlight that urban areas with high spore exposure see increased cases among those with asthma and COPD.
Treatment limitations
Aspergillus’s resistance to antifungals like itraconazole and voriconazole poses a growing challenge. Only two new antifungals have been approved in the past decade, and development is slow.
Low-income countries, particularly in Africa and Asia, struggle with access to existing treatments. The WHO warns that without progress, fungal infection deaths could double by 2030.
- Current drugs: Itraconazole, voriconazole, amphotericin B, posaconazole.
- New compounds: Two approved in 10 years.
- WHO forecast: Potential doubling of deaths by 2030.
Global unpreparedness
Global infrastructure for tackling fungal infections is inadequate. In Latin America, only 20% of public hospitals have fungal-specific tests. In Africa, this drops to 5%.
The WHO’s 2023 plan to enhance fungal pathogen surveillance progresses slowly due to resource shortages. Training for doctors to recognize aspergillosis is also limited, especially in rural areas.
