Pathogenesis – in sickness and in health

Steven Poole in The Guardian:

The Covid-19 pandemic has wreaked extraordinary destruction and misery, killing nearly 7 million people worldwide thus far and devastating the lives of many more. And yet, viewed through the long lens of human history, writes the public health sociologist Jonathan Kennedy, “there is little about it that is new or remarkable”. Previous pandemics have killed many more, both in absolute numbers and as proportions of populations, and so may future ones. Covid should be a wakeup call that helps us manage deadlier plagues in the future. But will we heed it?

Our very existence and success as a species, Kennedy argues in this fascinating book, has been shaped by bacteria and viruses. Where, for example, did all the other species of humans go? At one time, early Homo sapiens shared the Earth (and interbred with) the stronger, larger-brained and equally artistic Neanderthals, as well as the hobbit-like Denisovans. What happened to them? It could be, as some argue, that we simply killed them all, or that they were somehow less well able to adapt to climate change. But Kennedy explores the possibility that roving Homo sapiens from Africa, who had acquired strong immune systems on their travels, might have simply infected the already settled Neanderthals of Europe with a novel pathogen that they couldn’t fight off – just as the colonising Spanish, tens of thousands of years later, decimated the Aztec population with smallpox as much as with weapons.

More here.