Typhoid is an ancient disease.
It is caused by the bacterium Salmonella enterica serovar Typhi (S.Typhi) and spreads in contaminated water, food, and milk.
For thousands of years, typhoid was an invisible threat to both princes and paupers.
It killed up to one in five of its victims and made many others very unwell.
It was only after 1800 that new clinical, statistical, and bacteriological methods helped turn typhoid into a clearly defined and preventable disease.