“Killers of 1.6 million people every year world-wide,
fungi are emerging as some of the most lethal microbes of the planet
—and we don’t really know how to stop them.”
– Scientific American June 2021
It’s Memorial Day Weekend. We are just emerging from COVID-19 restrictions, and are looking forward to a near-normal summer. I and most of my friends have been vaccinated against COVID. Our world is looking brighter, and this scientific magazine lands in my mailbox! Can’t scientists give us a break from telling us about all the threats that surround us?
It even was cold, rainy, and very windy in the Northeast all three days of this holiday; no break from the weatherman either.
What’s to worry about fungi? A little mold on our wet shoes in the back of the closet, a bit of green on that old loaf of bread, a few mushrooms in our lawn during a wet spring, or the annoyance of a persistent, itchy rash between our toes? Fungi make spores and that is how they travel. The air around us is full of fungi spores. We inhale about 1000 such spores a day. There are over 5 million fungal species, but before you panic, remember that only about 300 cause human disease, mostly skin irritations and allergic symptoms. BUT there are four for five fungal diseases that can cause serious human illness, even death, and some immune-suppressing treatments of COVID disease have increased our medical attention to them..
A fungal pathogen very familiar to medical people for decades is “Valley Fever” caused by “coccidio”. It is not a national problem – occurring mostly in hot, dry California and Arizona. It infects about 150,000 people in that area annually, can cause serious lung and other organ disease, but it usually usually responds to one of the only five anti-fungal drugs available. Bacterial infections on the other hand can be fought with other 20 different drugs of several different types.
“Pneumocystis” is a fungus, as you may remember, is the fungus that was the cause of death in the first cases of HIV forty yeas ago. That fungus, like other fungi, cause “opportunistic infections” – infections that take hold in people with suppressed immune systems like in HIV and those already weakened with critical illness. The fungus “Aspergillus” caused massive pulmonary infections in a third of patients critically ill with the flu in 2018, and two thirds of those patients died. In one study of five U.S. hospitals recently, “Aspergillus” infected 10% of people with severe COVID disease.
The clarion call in this particular article is about an ubiquitous type of fungus, a yeast, “Candida auris”. Unlike the common Candida yeast that causes diaper rash, this species can kill as many as two-thirds of those it infects. A 2020 analysis found “Candida auris” present in 19 countries on six different continents and many were resistant to one or more of the three classes of drugs used to treat infected patients. In New Delhi in a 65-bed ICU two-thirds of the patients admitted with COVID who became infected by Candida auris died. Hence the sidebar, “A Drug-Resistant Killer on the Loose.” However, the bell is not necessarily tolling for you, unless you are critically ill and/or immune-suppressed, such as with severe COVID.
As we reacted rather numbingly to the sensationalism of this particular article in SciAm, we moved on to its article about 50 deep sea microbes recently discovered that appear not to be recognized by our immune system like other germs are. The recognition of foreign germ cells is the first step in launching our immune defenses. These microbes live two miles down in the cold, dark ocean so we are unlikely to encounter them, but 80% of them were completely unrecognizable to one of our first-line perceivers of foreign cells. If these microbes avoid our detection and do not stimulate our immune defenses, will they hurt us? Remember, these microbes were brought up from the sea floor, cultured in a ship’s lab, and studied ashore. Could they ever reach us? This is the stuff of science fiction!
Then I saw the article on slime that has a memory, that “remembers” food source locations, and that can successfully navigate mazes. My memory of the 1958 movie, “The Blob”, did not allow me to continue to read that article.
“Have a nice day.”
Ref: Scientific American June 2021