A team of scientists from Duke University has shown that global warming could enhance fungal infections. The study in question has recently been published, coinciding with the premiere on HBO and HBO Max from the series based on the video game The Last of Us. Given that this chronicles an apocalypse fueled by a fungus that changes its behavior due to climate change, the results can be somewhat concerning. But you have to take several things into account.
The research has not been carried out on humans, but on laboratory cultures and mice. In addition, the authors themselves acknowledge that fungal infections are not contagious as in The Last of Us and, furthermore, that in principle they would only pose a risk to immunocompromised people or with other pathologies.
Logically, these people do not deserve to get sick either. However, even if global warming were to drive fungal infections, they would be much easier to stop than viral ones. Should the results be taken into account? Yes, but without falling into alarmism.
Fungal infections and global warming
There is something true in the plot of The Last of Us. This is because humans are safe from many fungal infections simply because our body temperatures are too high for them. It’s not exactly as reported in the series. In the first chapter, in a flashback to the 1960s, an epidemiologist explains that fungi that could cause epidemics can only live up to 34°C. This is something very variable, you cannot generalize as they do. But it is true that the temperature of our body is not conducive to the majority. Yes for some. After all, fungal infections are not alien to our species.
Bearing this in mind, the authors of the research that has recently been published in PNAS They wanted to check if the increase in temperatures can really affect the behavior of the fungi. To do this, they took samples of Cryptococcus deneoformans, a pathogenic fungus that can cause everything from pneumonia to meningitis in humans. These were placed under laboratory conditions and were heated from 30 °C to 37 °C.
Thus, they saw that heating could affect their DNA, specifically the transposons, more colloquially known as jumping genes. These are pieces of DNA that have the ability to move from one part of the genome to another, changing the way other genes are expressed. That is, they can make genes used that would normally be silenced under certain conditions. Or otherwise.
Specifically, they observed movement in three genes, called T1, Tcn12 and Cnl1. The effects are not entirely clear; but, at least, it seems that they promote drug resistance in fungi.
tests on mice
All of this was seen when growing C. deneoformans in the laboratory. But it still remained to be seen what would happen if these fungal infections occurred in a living organism. Therefore, they proceeded to repeat the experiment, infecting mice.
Again, that activity started in the jumping genes. What’s more, it seemed to be much more intense in animals. And only 10 days after the fungal infection. All of this leads scientists to believe that heat stress promotes mutations and somehow helps fungi to adapt to the environment.
Fungal infections glitches in The Last of Us
Fungal infections are transmitted by spores. For example, in the case of C. deneoformans, spores that may be in the environment from the feces of other infected animals are inhaled.
The transmission through bites that appears in the series, as we have already seen in this medium, makes little sense. This is actually an advantage, since the spores are much larger than the virus, so it would be much easier to stop the spread through measures such as masks. As long as the population used them, of course.
In any case, and despite the results of this investigation, there is no need to fear an apocalypse like that of The Last of Us. Fungal infections in humans are not something new. Yes, they could be made worse by global warming, but more research would be needed to know to what level. Furthermore, if it did occur, it would be relatively easy to contain them.
Even so, there are already some fungi resistant to antifungals that affect vulnerable patients, for example in hospitals. You have to pay attention to all of this. And it is already being done, in fact. Beyond that, we can watch the series without worrying about parallels with reality. Although, coming from where we come from, it sometimes seems difficult to avoid them.