Aspergillus fumigatus, a dangerous fungus that can rot human tissue and cause life-threatening infections, is spreading fast across the United States and experts say the threat could get worse with rising temperatures. This airborne fungus, which releases microscopic spores, is nearly impossible to avoid and can lead to serious health complications, especially in people with weakened immune systems.
What is Aspergillus fumigatus?
This common environmental fungus causes a condition known as aspergillosis when its spores are inhaled. Most healthy people can fight off the fungus naturally without any symptoms or complications, but those with compromised immune systems, including cancer patients, transplant recipients, and people with asthma, HIV, or other chronic illnesses are at high risk. In some, the infection can lead to organ failure or even death.
There are several forms of aspergillosis. One of the most concerning is invasive aspergillosis, a rare but often deadly infection that can spread from the lungs to the brain, heart, or kidneys. Another is chronic pulmonary aspergillosis, which affects around 400,000 people globally and causes long-term damage to the lungs.
According to medical data, survival rates are grim. Only 59 per cent of organ transplant patients survive one year after developing invasive aspergillosis. Among stem cell transplant patients, that number drops to just 25 per cent.
Where is fungus spreading in the US?
Scientists say the fungus is spreading fastest in warm, humid parts of the US such as Florida, Texas, Louisiana, Georgia, and California. Even densely populated cities like New York, Houston, and Los Angeles are vulnerable due to ageing infrastructure and increased exposure to mould in old buildings.
Despite its growing impact, aspergillosis is not a reportable disease in the US, which means there’s no official system to track how many people are getting infected or dying from it. This lack of data makes it harder for health officials to understand the true scope of the threat.
Why is it getting worse?
A major reason for the increase is climate change. Aspergillus fumigatus thrives in warm, moist environments. It can even survive in compost piles with temperatures over 120 degrees Fahrenheit. As global temperatures rise, so does the likelihood of this fungus growing not just in nature, but also inside human bodies.
A recent University of Manchester study warned that if fossil fuel emissions continue at current rates, the fungus could spread by 75 per cent by 2100, particularly in the southern US. The research also suggests that changing climates may shift where certain crops grow and what kind of fungal infections people are exposed to in the future.
Adding to the problem is the use of azole drugs, a common class of antifungals. These are used not just in medicine, but widely in agriculture to protect crops. Overuse on farms has led to increased azole resistance in fungal strains. This means that the drugs often fail to treat infections in humans.
One study found azole-resistant strains of Aspergillus fumigatus in farm soil across at least seven US states. The mixing of different fungal types in soil is creating more powerful and resistant strains, making the situation worse.
WHO raises the alarm
The World Health Organization (WHO) has listed Aspergillus fumigatus as a top-priority fungal threat. It is becoming increasingly resistant to treatment and is already responsible for thousands of deaths globally each year.
Hospitals in the US are stepping up mould inspections and turning to more powerful antifungal medications. Doctors advise high-risk individuals to take precautions such as avoiding gardening, soil, and mouldy environments, wearing masks in dusty areas, and maintaining good air quality in homes and healthcare settings.
The WHO is calling for immediate global action including faster diagnosis, better drugs, improved training for medical professionals, and investment in new treatments, especially those tested for children.
With the threat growing and the climate warming, experts warn that we may only be seeing the beginning of a larger fungal health crisis.
