Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Mallon, commonly known as 'Typhoid Mary,' was an asymptomatic carrier of Salmonella typhi. She unknowingly spread typhoid fever through her work as a cook in the early 1900s.
5 Must Know Facts For Your Next Test
Mary Mallon was the first identified asymptomatic carrier of Salmonella typhi in the United States.
She infected at least 53 people with typhoid fever, resulting in three deaths.
Mallon was forcibly quarantined twice by public health authorities and spent nearly three decades in isolation.
Her case highlighted the importance of hygiene and sanitation practices in preventing bacterial infections.
The term 'Typhoid Mary' is now used to describe someone who unknowingly spreads disease.