It was also the impact of people, as infrastructure failed to keep up with the growth of the population: no sanitation systems to speak of, a dirty city with typhoid, malaria and dysentery.
Dysentery, typhoid, parasites, and other infections lead to hundreds of thousands of deaths every year, all because one in three people alive in 2017 don't have access to toilets and latrines.
Typhoid impacts around 16 million people a year across the globe, and even on the low end, that's 160,000 people capable of spreading infection just like Mallon did.
As cities grew and put more space between cows and people's homes, the longer Journey time allowed bacteria to grow in the milk, causing millions of people to get sick with tuberculosis, scarlet fever and typhoid fever.
As she folded it, so that her note was uppermost, she caught Gerald's words, " Your mother — typhoid — under no condition — to come home —" She almost sobbed.
He saw death and suffering up close, he was forced into cattle cars, forced to march, contracted typhoid fever, and was separated from his most beloved family members.