Wednesday, July 28, 2021

The Night of the Killer Yeast

In 1963, scientists Bevan and Makower described "Killer Yeast".

This was of great interest to the wine industry because "wild" yeast added undesirable characteristics to wine; characteristics like rotten-egg smells, excessive foaming, cloudiness and weird solvent smells (like model airplane glue). Killer yeast killed off other strains of yeast and cheerfully proceeded to spread through the must and produce a repeatable, salable product.

It was determined that "Killer yeast" were infected with a virus that they were nearly immune to but was lethal to yeasts that had not co-evolved with it

Fast forward to 2020:

There is a disease that is killing off millions of bats in North America. The disease is called White-Nose Syndrome (henceforth WNS).

Bats are communal animals, especially when hibernating. Most bats in the north hibernate in the relatively  few caves and mine shafts that are deep enough to provide an equitable temperature. Consequently, thousands and thousands of bats huddle together, touching, to conserve warmth. The crowding and the humidity are prime for fungi to spread.

And it has.

Some scientists investigated Pseudogymnoascus destructans, WNS's causal agent and determined that it existed on bats in Europe but did not cause WNS.

What the heck?

Further investigation revealed that various populations of Pseudogymnoascus destructans are infected with different types of virus, or no virus.

The challenge of introducing hypovirulence causing virus into wild populations is that the vigor of the disease causing organism must be dialed down to the point of producing a modest infection but it must not be dialed down so far that more vigorous strains overwhelm it and make it extinct.

The home-run scenario would be one where the specific virus could be cultured on an industrial scale in yeast and the growth media aerosol-sprayed into the air as the bats left their caves. As a point of fact, when yeast die of old-age they autolyse, that is, they explode and puke their innards out and that would include any virus swimming within them. The media can be filtered of yeast (large cells) and the active virus will pass through.

Consider the boon this technology offers the patient. Scientists could collect toe-jam from Brazilia, Manilla, Calcutta, Jakarta and other crowded, humid cities. They could screen them for Candida that exhibits killer or hypovirulence characteristics. The most promising candidates could be cultured using standard yeast-growing methods and equipment and a one time dip-or-drench would provide long-term protection against Athlete's foot and crotch-rot.

This could be a very timely contribution to the medical arts. There are recent reports of fungus diseases in the United States that are resistant to all standard antifungal drugs.

Unfortunately, there is little profit to be made with this technology. Once the hypovirulence inducing virus and/or yeast carrying those virus have taken up residence on the patient's skin, it will be there for a very, very long time. Repeat sales would be very, very low.

I would like to think that Universities and non-profits would investigate the possibility but many of their labs are funded by for-profit big Pharma and University bean-counters would see killer-yeast, hypovirulence research as a threat to that cash cow.


  1. Big pharma will never work on anything, and do their best to suppress anyone else that tries, that doesn't make money for them. Demonizing natural treatments from wild plants is the best example of their suppression efforts. And if their medicines maim, incapacitate or kill you that is OK with them as long as they make money. More obvious every day. That's why they insisted on legal immunity for their biggest venture yet. ---ken

  2. We never follow the total effect of something. Instead we see only what we want to see. Over time some bats will survive and pass that trait on to future generations and the killer yeast will die out to a large degree. Yup, lots of bats will die in the meantime, just like small pox caused millions of deaths in Europe when first introduced, deaths had fallen from over 50% to 15% in the 1760s after several hundred years of survivors passing on the ability to live through the pox.