Parasites and Piety

Sunday, February 5th, 2017

In This Is Your Brain on Parasites, Kathleen McAuliffe examines how tiny creatures manipulate our behavior and shape society, with a chapter on parasites and piety. One passage recalls Chapter 4 of John Durant’s Paleo Manifesto, “Moses the Microbiologist”:

It took thousands of years for agriculture to take off. Few cities in the Middle East, where the movement began, had more than 50,000 inhabitants prior to biblical times. So the perfect storm was slow to gather but, when it hit, a health crisis of unimaginable disruption and trauma ensued. These new diseases were far more lethal and terrifying than the versions manifested in the untreated and unvaccinated today. We are the heirs of exceptionally hardy people who were unusual in having immune systems that could repel these virulent germs. Those at the forefront of these epidemics likely fared far worse on average than our more recent ancestors. Consider the fate that awaited some of the first people to get syphilis: pustules popped up on their skin from their heads to their knees, then their flesh began to fall off their bodies, and within three months they were dead. Those lucky enough to survive the ravages of never-before-encountered germs rarely came away unscathed. Many were crippled, paralysed, disfigured, blinded or otherwise maimed.

It was exactly at this critical juncture that our forefathers went from being not particularly spiritual to embracing religion — and not just passing fads, but some of the most widely followed faiths in the world today, whose gods promised to reward the good and punish the evil. One of the oldest of these belief systems is Judaism, whose most hallowed prophet, Moses, is equally revered in Christianity and in Islam (in the Quran, he goes by the name Musa and is referred to more times than Muhammad). Half the world’s population follows religions derived from Mosaic Law — that is, God’s commandments as communicated to Moses.

Not surprisingly, given its vintage, Mosaic Law is obsessed with matters related to cleanliness and lifestyle factors that we now know play a key role in the spread of disease. Just as villages in the Fertile Crescent were giving rise to filthy, crowded cities, and outbreaks of illness were becoming an everyday horror, Mosaic Law decreed that Jewish priests should wash their hands — to this day, one of the most effective public-health measures known to science.

The Torah contains much more medical wisdom — not merely its famous admonishments to avoid eating pork (a source of trichinosis, a parasitic disease caused by a roundworm) and shellfish (filter feeders that concentrate contaminants), and to circumcise sons (bacteria can collect under the foreskin flap). Jews were instructed to bathe on the Sabbath (every Saturday); cover their wells (which kept out vermin and insects); engage in cleansing rituals if exposed to bodily fluids; quarantine people with leprosy and other skin diseases and, if infection persisted, burn that person’s clothes; bury the dead quickly before corpses decomposed; submerge dishes and eating utensils in boiling water after use; never consume the flesh of an animal that had died of natural causes (as it might have been felled by illness) or eat meat more than two days old (likely on the verge of turning rancid).

When it came time for divvying up the spoils of war, Jewish doctrine required any metal booty that could withstand intense heat — objects made of gold, silver, bronze or tin — to ‘be put through fire’ (sterilised by high temperatures). What could not endure fire was to be washed with ‘purifying water’: a mixture of water, ash and animal fat: an early soap recipe.

Equally prescient from the standpoint of modern disease control, Mosaic Law has numerous injunctions specifically related to sex. Parents were admonished not to allow their daughters to become prostitutes, and premarital sex, adultery, male homosexuality and bestiality were all discouraged, if not banned outright.


  1. Adar says:

    Phineas in the Bible caught the Hebrew man and a Canaanite woman coupling. Phineas killed them both and then stabbed the woman through the private parts as an indication of his indignation. Probably some sort of venereal disease spread from the Canaanite to the Hebrew. Folks back then “coupled” with animals in an unnatural manner as part of religious ritual.

  2. Gaikokumaniakku says:

    The exact history of Judaism is in dispute.

    The pork prohibition was related to social class and taxation in Egypt — lower-class people ate pork because temple priests couldn’t tax pork. (Taxes were collected by marching livestock across desert. Cows survived. Pigs didn’t. Thus pork was tax-free.)

    The history of Egypt fails to confirm the claims of the Old Testament.

    Religious Judaism is probably of very, very recent origin; possibly 440 BCE.

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