Read this first, then talk.
snopes.com

I can really understand and go for the explanation given for Mary Mallon's behavior. If you don't have a background in even basic biology then it would be extremely difficult to understand how you can spread a disease you don't even have so for Mary it would have been the most confusing thing to ever happen to her probably. I mean, if you don't understand basic germ theory then how are you supposed to understand that you can pass on a disease without getting sick?

I'm posting this basically cos I think that it really sucks for Mary that people apparently remember her as a monster. I can think of people doing far worse things (bubonic plague victims running through the streets of London in an attempt to spread the disease for example) and really what else was Mary expected to do for a living? I mean, it's not like she would have had many transferable skills where she didn't still risk passing the disease on, is it? I feel really bad for the poor, dead lady.