Out of curiosity, how does the CDC classify infectious disease?

Question

I have been reading about the Black Death of the 14th century and became curious as to how a disease is classified and the guidelines used to do so. Is the classification contingent upon mortality rate, number of persons infected, length between infection and onset of symptoms? The plague wiped out 1/3 of Europe's population, but how would it be classified now? I know the common cold could once have been a death sentence, but now we treat it with over the counter meds.

Answer 1

An infectious disease is any disease whose etiological agent can be spread from one source to other people, plants or animals. Infectiousness (communicability) has nothing to do with virulence, incidence or incubation.

You mentioned the common cold. Yes, people survive it routinely. But it is still infectious because the virus can be spred from person to person. Other infectious diseases aren't spread person to person, but rather through pointsources or exposures, like mad cow (Creutzfeld-Jakob Disease) via food poisoning.