Before the Black Death struck the Eurasian land mass, human beings seemed to have been in a blessed state. They lived in small crowded communities that were isolated from each other and there were no infectious diseases. There had been the odd outbreak now and again - the Periclean plague in Athens in classical times, and then, during the time of the Byzantine Emperors another plague called the Justinian, but these fizzled out. They did not go global.
The Black Death was different. It started somewhere in the plains of China and travelled along the Silk Road, its lethality depending on the way it struck: the bubonic form was the least lethal and tended to peak in the Autumn, if it went to the lungs (which it tended to do in a cold snap) then in was more lethal still and tended to prevail in the winter, and if it entered the blood then death was inevitable and could happen all year round. It came to the British Isles in around 1348.
According to this book, this particular plague started because of climate change. Small burrowing infected rodents came south when the world went colder which caused them to collide with the migrations of humans also seeking out warmer and more luxuriant pastures. It brought to mind another plague I read about a few years ago: also caused by rodents coming to the surface and infecting men - this time through their droppings - the Hanta virus plague in Arizona. In the Black Death case it was a bacteria, the Yersinia Pestis. The Y Pestis lives in the intestinal tract of fleas, when there are too many of them they cause a blockage making the flea starve. The flea then seeks out more food (the rodent) and vomits what it swallows back onto its victim, and since this vomit consists of bacteria the rodent becomes infected too through breaks in the skin.
The first indication of a plague then, was a sudden increase in dead rodents. Albert Camus mentions this in his novel, I remember, but few contemporary people made the connection at the time of the plague. Other animals were infected too, the only exception being the horse. The fleas don't like the smell of horse, apparently, and I remember reading somewhere that this may be why the nomads of the Steppe were not infected earlier.
The proportion of the population that died varied. The book postulated that this variation was due to the links of a community with the outside. Places like East Anglia were badly affected because they were challenged with bacterial strains from the Low Countries (which seemed to have a particularly lethal strain) and also from London. Two chapters deal with the evidence of how many died, and soon I became a little punch drunk. In chapter 3 they died in the Mediterranean and the Middle East, in chapter 4 in northern Europe. Approximately around 25-50% of the population died. A chilling thought. People reacted in different ways. Some adopted an Epicurean stance, eating and drinking and roistering because who knows what tomorrow might bring. Others adopted a more temperate approach: the plague, after all, was a punishment from God. Others took a path in between.
Then, in 1361 there was another plague - not quite as bad as the Black Death, but bad enough. Overall 20% died. Then, in 1369, another, and another and another, every 5-12 years. These tended to be less virulent but they came in frequent waves, each time sweeping away a percentage of the people, and it was the terror of this that some have said had the biggest impact. Overall, between 1349 and 1450 the population of Europe declined by 60-75%, the bulk from rural areas.
The rest of the book deals with the effect of such a massive depopulation. I found this particularly fascinating. It caused, or considerably helped, to rid western Europe of the feudal system as labour became more rare and valued. In the towns there were innovations such as water mills and wind mills, gunpowder and printing (although I have also heard that these could also have come from China). It averted overpopulation and overcropping of the land. It turned people from mystical anti-intellectualism to reasoning, and in particular the development of the scientific method. Hospitals were divided into wards and changed from sanatoriums to places that could cure. Stripped of teachers, the universities had to start anew and establish new colleges to make up quickly for the shortage of staff. Fewer classically-trained teachers meant that England turned from Latin and French to English.
After 1480 something shifted again, and the plague became a less frequent visitor, but by then there were other infectious diseases on the scene: in 1444 typhus, in 1426 flu, in 1485 the Picardy sweat, in 1495 syphilis together with 'red plague' (small pox), ague (malaria), measles, diphtheria and dysentary which were already familiar.
The people that survived were more wealthy and the book ends musing over why this era also brought a lowering of fertility. But given how the world must have been then - how uncertain and desperate - I think ti would have been reluctant to bring a child into the world too.