> Only sick people are disease vectors. That is not true for the casual meaning of "sick"; Typhoid Mary is the classic example of an asymptomatic carrier. Of

> Only sick people are disease vectors. That is not true for the casual meaning of "sick"; Typhoid Mary is the classic example of an asymptomatic carrier. Of course she is also an example of how responsibility can be traced even when asymptomatic carriers are involved, and an example of how negligence and refusal to take measures to prevent the spread of disease is antisocial behavior that can (or even must) be dealt with harshly.