While "The Last of Us" has us worrying about the zombifying ophiocordyceps, the reality of dangerous fungal infections will likely be more mundane — though potentially just as deadly.
Historically, our body's best line of defense against fungi has been our body heat. Human bodies are nice and warm, at an average temperature of 97.8 degrees Fahrenheit, which is typically too hot for infectious fungi to survive.
But as the Wall Street Journal reports, rising temperatures due to global warming could be giving fungi a new evolutionary opportunity to adapt to the stresses of heat. And that could be bad news for us warm critters.
"As fungi are exposed to more consistent elevated temperatures, there's a real possibility that certain fungi that were previously harmless suddenly become potential pathogens," infectious disease specialist Peter Pappas at the University of Alabama told the WSJ.
A rise in fungal infection deaths is already plenty to worry about. In 1970, US deaths due to fungal infections were only in the hundreds, according to the WSJ. But data provided by the Centers for Disease Control and Prevention (CDC) shows that in 2018, that figure had risen to more than 4,700. And as recently as 2021, that number climbed to 7,200 — although around 1,900 of those were COVID-19 associated cases, the agency notes, which is still a net increase.
But that could just be the beginning, as fungi adapting to the heat isn't the only consequence of warming temperatures. According to a study published last month in the journal Proceedings of the National Academy of Sciences, it could also be spurring certain fungi to evolve faster.
In the study, the researchers focused on cryptococcus, a genus of invasive fungi known for causing deadly diseases and infections in immunocompromised people, which the CDC estimates is already responsible for 112,000 brain infection worldwide deaths per year.
When raised in a warmer environment, they found that the fungi had a movement rate of "jumping genes" — genes that move between genomes and can cause mutations — five times higher than normal.
Asiya Gusa, coauthor of the study and a microbiologist at Duke University, told the WSJ that these changes could be responsible for fungi's adaptation to heat.
Meanwhile, other deadly fungi like candida auris, histoplasma, and coccidioides have been expanding their domain in the US since the 1950s, according to a recent analysis published in the journal Clinical Infectious Diseases.
Histoplasma was once limited to the midwest, but is now reported in 94 percent of states, the analysis determined. And according to coauthor of the analysis Andrey Spec, a fungal infection expert from the Washington Uinversity School of Medicine, Valley fever, which is caused by coccidioides and once only common in the southwest, is now being diagnosed in "significant numbers" in most states. Spec also affirmed that rising temperatures could be driving this spread.
"We keep saying these fungi are rare, but this must be the most common rare disease because they’re now everywhere," he added.
More on deadly fungus: Bad News: the Horrific Zombie Fungus in "The Last of Us" Is Real