When most people think of fungi, they picture something rather harmless, like a portobello mushroom, a jar of yeast on the kitchen counter, or perhaps a stubborn athlete’s foot patch that was eventually cured with a tube of cream. Fungi seem controllable. Well-known. Nearly domestic. For this reason, the scientists who are witnessing what is currently taking place in research labs and hospital wards across the globe find it extremely unsettling.
Mycology researchers have been raising concerns for decades, but the public and medical community have mostly ignored them. Other people, such as cancer patients, transplant recipients, and those already compromised by another condition, were thought to be at risk for fungal infections. The framing was never complete. It’s beginning to appear dangerously incorrect.
| Category | Details |
|---|---|
| Subject | Fungal Pathogens as Emerging Global Health Threat |
| Primary Organism of Concern | Candida auris, Candida albicans, Aspergillus, Cryptococcus |
| First Detection (C. auris) | 2009, Japan; independently emerged on three continents by 2012 |
| WHO Classification | Critical Priority Pathogen (2022 WHO Fungal Priority Pathogens List) |
| Global Deaths (annually) | Approximately 3.8 million linked to severe fungal disease |
| Global Invasive Infections | ~6.5 million per year |
| Fatality Rate (C. albicans) | At least 40% of systemic infections, despite treatment |
| Antifungal Drug Classes Available | Only 5 (vs. 38+ classes for bacterial infections) |
| Drug Resistance Status | C. auris resistant to 2 of 3 major antifungal drug classes |
| Key Research Voice | Dr. Arturo Casadevall, Johns Hopkins Bloomberg School of Public Health |
| Contributing Factor | Global warming enabling fungi to adapt to human body temperatures |
| Reference Website | WHO Fungal Priority Pathogens List |
In 2022, the World Health Organization released its initial list of fungal priority pathogens. Consider what it means that that list didn’t exist until 2022. Decades ago, bacteria received significant attention on a global scale. Since COVID-19, viruses have taken up a significant amount of political and scientific resources. In contrast, fungi have been underfunded, understudied, and frequently disregarded until patients are already very sick, creating a sort of scientific backwater. It was past time for the WHO list. It’s another matter entirely whether it arrived on schedule.
Currently, the name most likely to keep a hospital epidemiologist up at night is Candida auris. Before it first surfaced in Japan in 2009, medicine was unaware of it. It had independently surfaced in South Africa, the Indian subcontinent, and Venezuela by 2012—three different continents, three unconnected outbreaks. It was never transported by air. It just seemed to be the result of nature conducting its own experiments in silence. It has since appeared in Iran and Russia, and most recently, a new variation—a unique clade—was discovered in Singapore. According to the CDC, it is spreading quickly throughout American hospitals and is now becoming resistant to the last antifungal medication that effectively treated it.
The chair of Johns Hopkins’ Molecular Microbiology and Immunology department, Dr. Arturo Casadevall, has a theory as to why this is currently occurring. The temperature of the human body, which is approximately 98 degrees Fahrenheit, served as an unintentional firewall for millions of years. The majority of fungi just cannot withstand that level of heat.
However, fungi are being compelled to adapt as the planet warms. Those who are unable to withstand heat perish. Those who figure it out make it out alive. It turns out that some of those survivors can now infect us. In simple terms, Casadevall stated that it is always devastating when we are taken aback by nature. HIV was unexpected. COVID caught me off guard. Candida auris caught me off guard.
Speaking with mycologists gives me the impression that they are like those who have been pointing at smoke for years while everyone else debates whether the building was actually on fire. One of the four fungi that the WHO identified as critically urgent is Candida albicans, which is studied by Dr. Megan Lenardon, a microbiologist at the University of New South Wales. Every year, tens of millions of people contract relatively benign infections like thrush from Candida species.
However, in at least 40% of cases, invasive Candida—the type that leaves the gut, travels through the bloodstream, and invades organs—kills. It’s not a typo. 40%, even with the availability and proper use of antifungal medications. For comparison, the mortality rate from a serious golden staph infection is closer to 25%. One of the most dangerous bacterial infections in clinical medicine is less deadly than invasive fungi.
Fungal infections are extremely difficult to detect early, which contributes to the difficulty of all of this. The majority of hospitals lack specialized clinical mycologists on staff, and symptoms like fever, disorientation, and organ stress can resemble those of a bacterial infection. The window for successful intervention has frequently closed by the time a fungal cause is identified. When death occurs, the underlying illness is often blamed instead of the fungus that caused the death. This indicates that the number of fungal disease-related deaths worldwide, which is currently estimated to be 3.8 million annually, is most likely underestimated.
And perhaps the most sobering aspect is the treatment issue. Antifungal medications come in five different classes that can be used in clinical settings. Five. in contrast to the more than 38 classes of antibiotics used to treat bacterial infections. Due to the surprising biological similarities between humans and fungi, some of those antifungals are actually toxic to both human and fungal cells. It is truly difficult to create a medication that eradicates the fungus without endangering the patient because we share so much cellular machinery. The development of new antifungals is costly, time-consuming, and historically underfunded. Fungal vaccines are not even close to being used in clinical settings.
Candida auris colonizes surfaces in addition to infecting patients. Medical equipment, bed rails, and the floors of rooms used to treat infected patients. It is frequently not eradicated by standard hospital disinfectants. Once it enters a ward, aggressive protocols may be needed for months before it is completely eradicated. Casadevall is straightforward about this: once you need therapy, you’re already fighting drug resistance, so infection control is now more crucial than therapy. Right now, the most important tools are surveillance, isolation, and prevention. Additionally, they are the instruments that need ongoing institutional support and funding, neither of which have come to pass at nearly the required scale.
Here, it’s difficult to ignore the pattern. The world underinvested in respiratory virus pandemic preparedness for decades. Millions of lives were lost as a result of that disregard when COVID-19 struck. Mycology is in a similar situation to that of virology twenty years ago: experts recognize the importance of this field, but it only gets a small portion of the funding and attention it merits, and the general public has hardly given it any thought. A fictional fungal apocalypse briefly gained popularity thanks to The Last of Us. Nearly no coverage is given to the real version, which is slower, more subdued, and currently taking place in hospital isolation rooms.
It is genuinely unclear if a fungal pandemic similar to COVID-19 is imminent. It makes sense that scientists are wary of that framing. However, a more subdued, grinding disaster—more fatalities, more drug-resistant strains, and more immunocompromised patients left without viable treatments—is not what we envision for the future. It’s already taking place. Whether or not we are experiencing a fungal crisis is not really the question. How bad must it get before someone decides it merits attention is the question.
