Not a virus or bacteria, but this silent killer is spreading and climate change is helping it thrive

Scientists are raising serious concerns over the global spread of a dangerous fungus that can fatally damage human organs, particularly the lungs.

Known as Aspergillus, this airborne mold is now spreading at a faster rate, with researchers warning that climate change is creating ideal conditions for it to thrive. The fungus poses a significant threat to public health, especially to people with weakened immune systems, and may soon impact millions across continents.

How Aspergillus Affects Humans

Aspergillus fungi are present in soil, compost, and decaying vegetation, and they release microscopic spores that are easily inhaled. While most healthy individuals can resist infection, those with conditions such as asthma, cancer, HIV, COPD, cystic fibrosis, or recovering from organ transplants are at heightened risk. When the immune system fails to eliminate the spores, the fungus begins to grow inside the body, potentially leading to aspergillosis, a condition that can cause severe lung damage, organ failure, and even death.

The infection is particularly dangerous because it is difficult to detect. Symptoms such as fever, coughing, and fatigue can mimic more common illnesses, delaying diagnosis and treatment. Mortality rates for invasive aspergillosis range from 20% to 40%, according to studies.

Climate Change Accelerating Spread

A recent study by researchers at the University of Manchester has identified climate change as a major factor behind the expanding presence of Aspergillus species.

Using climate models and simulations, the team predicts that rising global temperatures and changing weather patterns will push the fungus into new regions. Parts of North America, Europe, China, and Russia are expected to face greater exposure within the next 15 years.

Two key species—Aspergillus flavus and Aspergillus fumigatus—are of particular concern. The former thrives in hotter climates and could expand by 16%, while the latter, more common in temperate regions, could grow by as much as 77.5%, potentially affecting 9 million more people in Europe alone.

Meanwhile, countries such as Brazil and regions in Africa may become too hot for some Aspergillus species to survive, highlighting the unpredictable ecological impact.

Urban Centers and Vulnerable Regions at Risk

Urban areas like New York, Los Angeles, and other densely populated cities are particularly vulnerable due to aging infrastructure and concentrated populations. California has reported the highest levels of exposure, with factors like humidity and intensive agricultural activity aiding fungal growth. States including Florida, Georgia, Louisiana, and Texas have also detected the presence of the fungus.

Researchers say that continued fossil fuel use and lack of mitigation efforts could worsen the spread of these pathogens. Norman van Rijn, a researcher involved in the study, emphasized that fungal pathogens have been understudied for too long and are now adapting to climate shifts in ways that make them harder to combat.