You probably know what the title means at a glance.  If I hear another advert telling me some product kills 99.9% of germs, I swear I will scream and curl up in the foetal position if my old bones can manage it.  I mean why???  It is a very temporary, tiny, and pointless win in a limited area for the most part.  There are about 400,000,000,000 cells in the human body.  Every one of the cells is outnumbered about 10:1 by germs such as bacteria, viruses, fungi, phages etc.  There is a whole zoo inside a happy healthy human being, who may be described as a high-rise appartment for germs.  An adult has probably about 8kg of germs.  Many of them essential to our survival, many of them going about their own business and doing no harm and a few that are troublesome.  We need bacteria in out gut to be able to digest many types of food.  In our western diet, our food range has contracted from that of our ancestors by concentrating on growing few crops such as wheat and rice, and a relatively small range of vegies in the supermarket.  A hunter-gatherer in the Amazon jungle for instance would eat a much wider range of food.  We probably have about 400-500 species of bacteria in the gut and the hunter-gatherer more like 1400.  Some people with chronic intestinal problems are currently being treated with an influx of germs from a healthy person, a pill nicely coated with a hard sugar shell to help the medicine go down, to boost germ levels.  Jokingly referred to as a “transpoosion”.  An awful pun on transfusion.  Some are treated with an influx of worms, but a pig variety which can’t reproduce in humans so there is just one generation.

The resident germs are also our first line of immune defense.  They defend their human real estate with turf wars against any intruder stealing their resources.  You are probably wondering what our immune system is doing in all this. For a long time I thought the immune system acted as “ah ha, an intruder lets kill it”.  But it is more sophisticated than that.  Like cops in a big city, it lets citizens doing no harm alone and goes after the bad guys.  Sure cuts down the work load. There are hints all around about the usefulness of germs to us.  Babies are usually born face down and contact germ rich material from the mothers anus in the great struggle to get the little bastards out.  Specialised cells also kidnap useful germs from the gut and transfer them to the vagina before birth.  As a back-up, they also take them to the mother’s milk.  Babies need germs to even be able to digest mother’s milk.  Ruminants are even more dependent on bacteria than we are to digest their food and often lick their mothers mouth to pick up the germs.

OK.  I hope I have persuaded you about how much we need germs.  So what happens if a child doesn’t get enough exposure in early years?  What if over-diligent parents Glen 20 everything in sight? Their children are more likely to develop auto-immune diseases later in life.  The “hygiene hypothesis”.  Google it.  Hay fever, forms of arthritis, multiple sclerosis and many other modern diseases on the rise are auto-immune conditions.  These conditions are almost unknown in peasant societies with animals such as goats, chooks, pigs etc in everyday contact.  You would be doing your kids a favour by having a dirty smelly dog.  A wonderful vector for germs.  A nice slurping lick over baby’s face to clean up the dribbles of mashed pumpkin.  Sooo much better than a santised wipe.  You will not be surprised to learn that I encouraged my kids and grandkids to romp naked through the rainforest and plunge into swamps.  I remember just a couple of years ago my youngest grandkid, less that 2 years old, was swamp diving totally naked and disappeared from sight.  He’ll be coming up soon I thought  ….. anytime now ….  will be soon… just before I went into panic mode he appeared crowned with mud and rotting leaves and laughing his head off.  A large ongoing study in Belgium found that auto-immune diseases are a city disease.  Kids brought up on farms, especially farms with animals are at much lower risk.  This is because in the neolithic ages with kids brought up in caves, they needed a robust immune system.  Given too little to do, the immune system can get over sensitized and loses the capacity to distinguish friend from foe and can attack the body’s own cells.

My own little rave here is about the fact that if we try to sterilize the world, kill 99.9% of germs, it will backfire in a catastrophic way.  Many microbiologists and biologists are telling us that we are immersed in the whole ecosystem and we need to protect it and preserve it for our own welfare and health.  Not just because some very pretty birds and animals are becoming extinct, but because our very lives depend on it.  There is plenty of sentiment about preserving cuddly things like koalas, and beautiful things like birds, but there is also a world wide catastrophe happening right now as insect numbers are crashing, even in places far away from the onslaught of agricultural spraying.  Even in Possum Valley, still rich in every kind of bug, I have noticed a steady decline in extravagant swarming events that stunned me when I first came here 46 years ago.  Fireflies, once a reliable dazzling display are now rare and I see but a few in the year.  Beetle swarms and moth invasions used to litter the house but now don’t happen.

So I am trying to put in a good word for the most maligned creatures on the planet.  Germs.  We need them as most fundamental to the web of life.  Some are bad for us such as covid, and we should focus on the nasty ones, not try to kill the millions of species indiscriminately.  The fundamentals of hygiene still apply, like hand washing and containing sneezing and coughs, but I do believe the old adage applies “a home should be clean enough to be healthy, but dirty enough to be happy”.


  1. Peter says:

    The manufacturers will claim that the universally common figure of 99.9 is a legal dodge to get around the fact that since they can’t test every sample in its entirety, they recognise the fact by claiming only 99.9 efficacy. What is worrying is how the 0.1 that only get a whiff survive, breed, and pass on their immunity. But that wasn’t your point, really, was it? I agree, a robust defensive system needs regular training, regular testing and refinement, regular updating and regular challenges – whatever the size or nature of the battlefield. Sadly, as you note, the insect world is losing the battle, as the absence of evidence on windscreens and registration plates attests.

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