Pathogenesis: A History of the World in Eight Plagues

by Jonathan Kennedy

Many of these DNA sequences don’t seem to do anything in the human body, but retrovirus infections allowed our distant ancestors to acquire the capacity to perform functions that are fundamental to human existence. One remarkable example is a gene inherited from a retrovirus infection about 400 million years ago that plays a crucial role in memory formation.

The scientists concluded that a crucial function of the placenta didn’t emerge gradually as a result of evolution by natural selection but was suddenly acquired when a retrovirus inserted its DNA into our ancestor’s genome. If one of our distant ancestors hadn’t been infected by a virus hundreds of millions of years ago, humans would reproduce by laying eggs.

Christians would have been able to reduce mortality by up to two-thirds just with basic nursing, such as providing food and water.[48] The fact that so many more Christians survived, and that Christians managed to save pagans abandoned by their families, would have provided the best recruitment material any religion could ask for: miracles.

By the end of the fourth century, the total number of priests, monks and so on was half the size of the army, so Christianity was a considerable drain on manpower.

Without the lethal effects of Yersinia pestis, it is almost impossible to imagine that Islam would have blossomed from a sect with a small group of followers in the Hijaz to a major religion practiced by almost a quarter of the world’s population, or that Arabic would have gone from being the language of a few desert tribes to one that is now spoken by almost half a billion people across North Africa and the Middle East.[72]

In 1829, William Burke was convicted and hanged for murdering sixteen people and selling their bodies to the University of Edinburgh Medical School for dissection. His co-defendant, William Hare, turned state informant in return for immunity.

The system is so inefficient that if the U.S. had a national health service like the UK’s, its health outcomes would improve and it would save almost 2.5 trillion dollars every year. Deaton and Case point out that the dysfunction in the U.S. health care system is, in monetary terms, more of a handicap than the reparations that Germany had to pay following the First World War.