The bones of history: new research in disease history

Today I am taking a break from the modern world to write about two new studies that shed important light on the past. Both are to do with the history of disease - something I’ve been interested and working on for many years.

The two papers that caught my eye came out in the last few days and are absolutely fascinating and (yet again) wonderful examples about the advances in the sciences that are fundamental to historians working today.

The first paper appeared in Science last week and was published by a team led by Bruno Romero González. It focuses on smallpox and the implications of its genomic divergences in the strains that proved lethal in the Americas after Europeans arrived after 1492.

Smallpox was one of the greatest killers in human history. As I noted in The Earth Transformed, the pathogen is estimated to have killed 300 million people in the twentieth century alone.

For those who contracted the common variola major form, mortality could reach 30 per cent; many survivors were left scarred, blind - or both. Smallpox is one of the world’s great medical success stories, though, with the disease eradicated following a major international vaccination campaign. The last naturally occurring case was recorded in Somalia in 1977; in 1980 the WHO declared the disease eradicated.

Nowhere was smallpox more devastating than in the Americas. Europeans carried brought a host of diseases with them when they crossed the Altantic to which indigenous populations were immunologically naive.

The result was catastrophic illness, suffering and death - and contributed to one of the steepest demographic collapses anywhere in human history, worse, probably, than during the Black Death (note: please do pick up a copy of my book if you want to know more!)

Smallpox was first documented in the Caribbean in 1518; two years later, it had reached Mexico by 1520; by 1525 it was prevalent in the Andes, spreading amongst the Inca and their subject populations. In the Americas as a whole, the disease is estimated to have killed at least 3–4 million people, and possibly substantially more.