Are people too clean for their own good?

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Most Westerners regard their own countrymen as being reasonably clean and perhaps citizens of other nations may not be quite so hygienic, some even outright dirty. But if you spend even a few minutes in the public toilets at airports or service stations you will come to a different conclusion. At service stations, too few people wash their hands before leaving, at airports it is a little better. So perhaps, airline passengers are a bit more hygienic than car drivers, but still the result is not very encouraging.

It seems that families trust that even elementary topics are taught at school, and schools believe that these basic rules have been learned at home. Hygiene is the most important factor that prevents the harmful effects of harmful organisms or adverse chemicals; everything else is far less important. Therefore the basics should be taught at home, though it cannot hurt if this information is repeated at school.

Hygiene fallacies

A kind of mystique has surrounded hygiene in the past few years. The theory is individuals today are keeping their environment too "sterile" so that they have then no resistance towards any sort of environmental stress. According to proponents of this theory, it is advisable to allow the individual’s immune system the chance of practicing with "natural" environmental factors. At the extreme end of this fallacy some people think it is better not to vaccinate children, but to let them catch (and suffer) the "natural children's diseases." Quite recently the so called hygiene hypothesis of allergy has provided another string to the bow of this theory. According to this hypothesis, children born in farms and especially those in abundant contact with animals tend to be less prone to allergies than other children.[1]

In fact there are several fallacies in the above logic. The first is that those twenty or so infectious diseases that are preventable by vaccination do not represent even a minuscule fraction of the microbial population. Thus, even if we prevent our children from contracting diphtheria, whooping cough, tetanus, haemophilus meningitis, measles and maybe a few other diseases, there is a plethora of possibilities to train their immune mechanisms with the remaining thousands upon thousands of other microbes. These typical children’s infectious illnesses are probably not even very ancient diseases; most of them developed from diseases of domestic animals after these were tamed less than ten thousand years ago. Therefore they cannot be "useful" to humans on the basis of a long history of cohabitation.

In addition, the microbes believed to be involved in the "hygiene hypothesis" of allergies are not the typical causative agents of infectious children's diseases. They are probably normal microbes of the gut or live naturally in the soil, possibly gram-negative bacteria whose cell constituents may be useful in directing the immune mechanisms to recognizing the correct stimuli rather than being activated by typical allergens such as pollen. Therefore it may be more rational to take children outdoors to play in the forests and fields where they will encounter these microbes (if we want to train their immune system) rather than being afraid of too much hygiene in the home or even worse, not taking the children to be vaccinated.

Risks come from contacts

The importance of hygiene is due to the simple fact that population density of human beings is completely different from what it was for hundreds of thousands of years. Human beings developed in conditions where there were very few people in close proximity with each other, and where an individual very rarely encountered a stranger.

Today, microbes have excellent possibilities to spread rapidly among thousands, even millions of people who all live close to each other. This is very different from the time when humans lived in tribes of fifty or at most a hundred, with the next tribe being perhaps tens of kilometres away. Today’s human communities are as vulnerable to infections as the chickens on a battery hen farm or the pigs in an industrial scale piggery, so called factory farms of thousands of animals. As any veterinarian knows, an epidemic can ravage the whole population of these “farms” with ferocious speed. This is also why health authorities and experts are so concerned on the spread of the influenza viruses.

The history of urbanisation offers a good example of the importance of hygiene. Cities and towns were not healthy places to live until the late 19th century (in other words, four or five generations ago). Cities grew only because new people poured in from the countryside, but within towns, death rates were permanently higher than the birth rates and without migration, all towns would have become emptied sooner or later. This trend was only reversed when the importance of hygiene was understood, and that was not until the late 1800s. The quality of the living environment and the standards of drinking water and food improved; only then did towns become hygienic and safer.

Cleanliness must be learned

Chimpanzees can drop banana peels from wherever they happen to be, as well as any other droppings, without causing much danger to other chimpanzees. This is not true with humans living in large communities, and if they are careless and sloppy, the result is high child mortality and sick adults as is the case in many developing countries. The natural inherited sense of cleanliness seems to remain at the same level as that of a chimpanzee – like many other inherited traits. Therefore cleanliness and hygiene depend on training and education – many people today talk about the helplessness of the current generations; these traits are not in the inborn nature of humans.

Therefore there is every reason why children need to be taught to wash their hands after going to the toilet and before meals, and this must be done at home when they are toddlers. Similarly, there is every reason to teach children to brush their teeth as soon as they have teeth to brush. Since caries bacteria and other pathogenic bacteria can be transferred from mother to child, no spoon or other utensil that has been in her mouth should ever be put into the child's mouth. Little children should not be kissed on the lips but on the cheek. Of course, some may protest that kids even eat dirt in the backyard. That is true, but it is more likely that disease-causing bacteria reside in the mother's mouth than in the dirt in the backyard. The vast majority of soil bacteria are innocuous, and children can train their immune systems with these micro-organisms.

Food hygiene is another crucial point and here the most focal point is the kitchen. In order to prevent the spread of salmonella or other intestinal pathogens, a knife used to cut uncooked meat should never be used to slice bread, vegetables or anything else that will not be cooked. The knife must be first washed thoroughly, as well as the hands of course. This sounds so trivial as to be obvious, but efforts to improve hygiene in the food industries or by the authorities are worthless, if the weakest link is in consumer's own kitchen.

Taking care of hygiene in what we do on an everyday basis is the foundation stone for health. If this basic fact is forgotten, then any efforts by the authorities or manufacturers will be in vain.

Notes and references

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