Microbiologist David Thaler on COVID & what we know about the invisible living world. We are encountering an intrusion of the micro-world, as COVID swamps country after country. Explore with world expert microbiologist David Thaler – an American scientist working out of Basel Switzerland. Visible plants and animals are in decline globally. Is the microbial world in trouble as well? We can’t live without it. Be ready to challenge your mind.

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This interview is not strictly about the COVID-19 pandemic. Of course the public health emergency comes up several times, but Dr. Thaler takes us a step back to consider where a virus likes this comes from. We need to consider the universe of microbial life in a new way. Every major university or medical school teaches about infectious diseases. Some have entire schools dedicated to that. We grow up being taught to fear and avoid microbes. But this unknown world of living things is literally within our bodies and necessary for our lives.

David raises the example of “anexic” mice. These are born by Cesarean in a lab and kept germ free. They can barely digest food and don’t live long. He says we probably have as many non-human cells in our bodies as human ones – and can’t live without them. We are really not independent “humans” but colonies of life.


For me, one of the key take-aways from this hour with David Thaler is: most of microbial life is not predatory or adversarial, but symbiotic. Life works together, adapts to each other, and usually evolves toward general success. Some viruses inhabit our body, taking up and protecting their space (their “information space”), keeping out possibly more harmful life forms. He says if microbes wanted us dead we would be dead. But they seek symbiosis for the most part (diseases may be the exceptions, but even most of those try to leave some host living). Trying to sterilize or annihilate microbial life is not just impossible, it would be suicidal. So maybe we should explore the tiny world with admiration and curiosity rather than fear.

The Coronavirus is different from most of the microorganisms our body knows, and that is partly why it is so infectious. Our immune system has not encountered this life form in the past, and so has no ready response to defend us. COVID-19 is “new information”. Remember, a virus is essentially information in a chemical code we call RNA.

As a microbiologist, David Thaler was writing about public health and ways to inhibit contagion in February 2019, about 8 months before the arrival of COVID-19. The paper is: “Precision public health to inhibit the contagion of disease and move toward a future in which microbes spread health”.

“Minimizing microbial-human interactions would be a mistake. There is evidence that microbes previously thought of at best “benign” may actually enhance human health.”

Such a novel idea! Maybe health can be contagious, and not just disease! Later in the interview David proposes ideas to “nudge” microbial life in directions beneficial to us and other macro life. He continues:

A “microbial Neolithic revolution” is a possible future in which human microbial-associations are understood and managed analogously to the macro-agriculture of plants and animals.”

David is also sole author of a published call to save samples of COVID-19 variants in a coherent way for long-term study. This is the letter, published April 2020 in the journal Nature. “COVID-19: sample for future analysis”. I ask whether this is a safe idea, considering the possibilities for use in germ warfare in the future. For similar reasons, samples of Smallpox were kept limited or destroyed. We already have the suggestion even in intelligence reports the COVID-19 virus may have escaped from a lab, whether for research or weapons research. Or it may have come from a bat. We don’t know, even now.

David replied “The problem of killing people is solved.” That is, we already have so many ways for mass murder (including nuclear weapons, anthrax, and too many more). Thaler points out the virus is already mutating many times over. If we don’t collect samples now for future study, we may never know what was out there or how to prevent it again.

Apparently the UK Government has created a COVID-19 library, as David suggested. The Sun newspaper (UK) reports in February 2021:

“THERE are around 4,000 coronavirus variants now in circulation around the world, the UK’s Vaccine Minister has revealed. Nadhim Zahawi said there was a “library” of Covid mutations being stored to ensure the country was ready to respond with updated vaccines.”


When we talk about “microbial life” what kind of creatures does that include? I ask David to give us examples. If we could shrink down to the micro-plane what would we see? At first, I was frustrated David would not describe any particular tiny life-forms. Then with more digging, I realized it is not possible to answer that question with any reality.

See this YouTube video: “Microbes Don’t Actually Look Like Anything” uploaded by Journey to the Microcosmos.

Maybe we can understand with an example from another paper Thaler co-authored on microscopic life. That was just published in March 2021. It turns out virus not only infects animals, but also invade bacteria found in our intestines. I ask David to explain what a bacteriophage is, and why he helped create a public collection of them in Basel.

But again David and the other authors say “traditional model systems did not keep pace with the recent massive expansion of the field.” Why can’t we keep up even in a limited class of virus life? Because as Thaler tells us, every scoop of mud from a river or lake contains new forms of microbes never seen or cataloged. We don’t know how many different microbial forms are out there. Nobody can count them. Since we don’t know the way micro biodiversity is going, we really don’t know which way all of biodiversity is going, even though macro diversity is in decline. Microbial biodiversity is yet another environmental issue!

There is no way to catalog micro species – and that is made even harder because Thaler says there is more variety (read strange forms) of microbial life than macro life. An Oak tree may be much closer to an Ant than microbes are to each other. Their biodiversity is immense and always changing. Microbes today are not living fossils surviving over billions of years. Some that Thaler studies from the Basel sewage system are brand new because they depend on human infrastructure like sewers. Microbial evolution is not over either.


Although unsatisfying, the point of Thaler’s new paper is simple: we don’t know the current state of the micro-world. When it comes to his latest paper is “Is Global Microbial Biodiversity Increasing, Decreasing, or Staying the Same?” – Thaler looked around his field and found (a) nobody knows the answer, and (b) nobody had even formulated this important question!

Biodiversity of macro plants and animals is falling rapidly. We have records of some of it. There is an argument that micro-organisms living symbiotically with those disappearing animals and plants (and insects) must be falling, as their hosts fail. That is stronger because Thaler tells us so much microbial life is more oriented toward its host than to any other microbe. They are specialized, and may lose as their hosts lose.

However there are other possibilities. For one thing, scientists guess there are more microscopic creatures living far below the Earth’s surface than interact with macro life. A huge mass of microbes live up to 10 kilometers (6 miles) below the surface in a hot environment that never gets light from the Sun or rain. I have seen guesses that the total mass (weight) of those microbes could be greater than the entire weight of all living things on the surface of the planet. The deep microbe world would presumably not be affected by even a mass extinction event far above them. They could serve as a font for replenishing life on Earth after any disaster. There is a network of scientists looking into deep life, at the Deep Carbon Observatory (DCO). Here is a link to that project (although my browser warned me their security certificate has expired and the site may be unsafe…).

Another possibility: microbes are expanding their biodiversity independently of macro plants and animals. Here David goes to the astronomical model of expanding space. Science finds the Universe is expanding. In a sense, Earth – tiny as it is – is becoming even less significant in ever-growing space. Similarly, the information space where we find microbial life may be expanding. They may continue to find new forms and places to inhabit. Again, we have no capability at present to know. Considering we need microbes to survive, and what just happened when a new virus arrives in COVID, I think we should invest a lot more in exploring micro-space right here on Earth, than we do in space travel to another planet.

All through the interview David Thaler refers to quotes and works of other great scientists. These include his colleague, the late Joshua Lederburg, pioneer in microspecies genetics; American environmental scientist Jesse Ausubel; Nobel scientist Alfred Hershey; and Isidor Isaac Rabi, discoverer of NMR nuclear magnetic resonance.

For me, David describes three models of thought as beginnings to understand the invisible world of microscopic living things.. We can use the astronomical analog, where there are clusters of life and space; we can investigate the micro plane as a kind of information space; and thirdly as a kind of procession in time. These life forms change so rapidly we cannot keep up. David tells us a microbe can evolve about a trillion times faster than humans. Microbiology operates almost on a different plane in time, which makes it difficult (perhaps impossible) – to capture, or even view.

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