The infamous carrier of typhoid fever, was Mary Mallon, also known as Typhoid Mary. Typhoid Mary was identified as a spreader of typhoid fever, yet she refused to self isolate herself. In 1907, she became the first carrier in the United States to be identified and traced. She was a cook in New York, who was directly responsible for 51 cases and three deaths, although indirectly responsibly for countless more. Typhoid Mary is a term for people who spread disease.
For more information about Typhoid Mary go to the Wikipedia page on Mary Mallon.