12/26   What's the difference between "infectious" and "contagious" when
        talking about diseases?  Thanks.
        \_ contagious is via the air
        \_ This seems to be pretty much a distinction without a difference.
           Some people try to call things you can catch by proximity
           "contagious", so while both are infectious, rhinovirus would be
           contagious, HIV would not.  But I don't know of a standard,
           widespread distinction.
           Here's another possible distinction:  Infectious means a disease
           caused by a micro-organism. Contagious means an infected person
           can transmit an infectious disease to another person
        \- i am not an expert in this, but my understanding is: contagious ->
           you can get it from another person [so this is probably what you
           are thinking both mean], but infectious means it is caused by an
           "infectious agent" ... e.g. if you cut yourself and get dirt in the
           wound and get a strep-caused problem, you have an infection but
           it wasnt contagious. so infectious is from "what" causes the
           disease. contagious is focused on the "how" the transmission
           occurs. what i am not sure about is what parameters apply to
           contagious, e.g. does it have to be same species, does it just
           include proximity or contact ... presumably something like
           getting a prion disease from eating mad cow beef isnt considered
           contagious ... since you are getting it via the medium of food.
           same for getting infectious malaria from a mosquito bite.
           now if somebody can explain the difference between iatrogenic
           and nosocomial, i'd be delighted.
        \- In practice they can be used sloppily but in "theory",
           contagiousness is a QUALITATIVE MEASURE of how easy it is
           to CATCH from another person [animal etc], and "infectious"
           gets at whether the cause of the disease is an INFECTIOUS
           gets at whether the CAUSE of the disease is an INFECTIOUS
           AGENT [bacteria, virus etc, as opposed to structural
           defect, toxin, chemical, radiation etc]. So it is reasonable
           to say "airborne influenza is MORE CONTAGIOUS than ebola"
           and to say "ebola is an infectious disease while osteoperosis
           is not" [pace, some h pylori type discovery].
           can somebody explain the difference between NOSOCOMIAL and
           IATROGENIC. ok tnx.
           IATROGENIC. ok tnx. --psb
            \_ o.k. I probably won't do as good a job as the above, and
               i'm no expert, but my understanding is that NOSOCOMIAL is
`              particularly in regard to maledies resulting from being
               in a hospital, where as IATROGENIC is used less
               specifically to describe any treatment-caused ailment.
               So that MRSA (resistant staff) is most likely to be
               referred to as nosocomial, whereas my fucked up shoulder,
               being directly attributed to the surgery, as opposed to
               the hospital per-se, would be more likely to be called
               iatrogenic.
               iatrogenic. -crebbs
               \- oh fair enough ... that seems like a meaningful
                  distinction. one is GEOGRAPHIC and one is SIDE-EFFCTTING.
                  so if i take my wife to the doctor and i get ill while
                  sitting int he waiting room, that is NOSOCOMIAL but not
                  sitting in the waiting room, that is NOSOCOMIAL but not
                  IATROGENIC. meanwhile, if i get an infection from self-
                  injections of insulin, that may be IATROGENIC. --psb
                  \_yep.  (assuming, the injections were prescribed, if
                    not I don't think it counts, unless perhaps you
                    consider yourself a Doctor of some kind :) -crebbs