Profile: The Fungal Detective

When the blockbuster television series “The Last of Us” riveted millions of viewers during the first quarter of 2023 with its premise of a mass fungal infection that turns people into zombielike creatures and decimates the world population, the media turned to Mat Fisher for fungal expertise.

“The show was scientifically exciting enough to draw people into the wonderful world of fungal biology,” says Fisher, a professor of fungal disease epidemiology at Imperial College London. “We welcomed the attention and our ability to correct, or at least educate, viewers on why this wasn’t a likely scenario.”

Far more exciting, though, is Fisher’s groundbreaking work on the real-world fungal scenarios posing major risks to amphibian populations and public health around the world. His innovative application of genetics and genomics has provided new insights into how fungal species form, migrate across the planet’s surface, and drive emerging diseases in human, wildlife, and plant species.

After earning a PhD in parasitology from Edinburgh University in Scotland, Fisher had a migration of his own, moving from his native United Kingdom to UC Berkeley for post-graduate research in the fungi-focused lab of John Taylor, who was then a professor of plant and microbial biology. “John had faith in his investment in the individual,” Fisher says. “He trusted he’d hired a keen scientific mind and would just let you go off and make discoveries without overly steering or micromanaging.”

By employing the emerging PCR (polymerase chain reaction) technology to characterize fungal variants, Fisher established the evolutionary framework that he later continued to apply throughout his career. His first breakthrough came in Taylor’s lab, when he used genetic variation to delineate two species of the fungus that causes Valley Fever (coccidioidomycosis).

Fisher has published more than 240 fungal biology papers since then. He has studied the fungus Aspergillus fumigatus in relation to everything from COVID-19-associated pulmonary aspergillosis to its role in an aspergillosis outbreak among kākāpō, an endangered New Zealand bird. He has compiled compelling evidence that use of the same antifungals on crops and in hospitals to treat aspergillosis patients is driving resistance and negatively impacting patient outcomes. He’s now studying the next generation of antifungal drugs, which just received EPA approval for field applications. “We want to know if this same problem of dual-use of antifungal chemicals raising resistance in fungal pathogens is going to happen again,” he says.

Fisher has garnered the most attention for his detective work on Batrachochytrium dendrobatidis (Bd), the fungus behind the disease chytridiomycosis, which is causing a precipitous decline in amphibian populations worldwide. By collecting and sequencing Bd isolates from around the globe, he pinpointed the ancestral origins of Bd in Southeast Asia and tracked its worldwide spread through traded amphibians. He and colleagues not only identified an effective antifungal treatment for infected animals but a disinfectant that eliminates the fungus in the habitat. These teams successfully applied both to remedy infected sites in the Balearic Island of Majorca, the first time a wildlife fungal disease has been eradicated in nature. And now Fisher applauds the World Health Organization’s 2022 release of its first-ever list of fungal priority pathogens for focusing overdue attention on the global health threats posed by fungal infections. “It was a heroic effort by the WHO,” he says. “They’re following it up with a blueprint for action. Where the WHO goes, others will follow.”

Looking back on his journey from training at UC Berkeley to his current professorship, Fisher says that the common link is his fascination with fungi themselves—how this diverse kingdom, often invisible to the eye, has an outsized impact on human patients, plants, animals, and the environment. From the beginning, he recalls, “Research in John Taylors lab captured my imagination as I learnt how little we knew about these extraordinary organisms. There was a world of discovery to be made, and almost all questions that you asked were relevant.”