In this episode of the SciShow, host Michael Aranda tells the story on the infamous Typhoid Mary, the typhoid carrier that had a job as a cook and infected over 50 people in the course of her lifetime. Typhoid Mary was twice quarantined by public health authorities and spent nearly three decades in isolation before she died in 1938.

The famous symptomless carrier of Typhoid Fever, Mary Mallon, never felt the effects of the fever, but never recovered from a medical system that didn’t know how to treat a carrier of the disease.

[Source: SciShow on Youtube]