Jeffrey Lotz jlotz at
Mon Apr 3 14:24:05 EST 1995

In response to Zelmer

The term "endo-symbiotic" as a synonym of 
"not-free-living" of course does not 
include "ecto-symbionts". Therefore, if we 
are to use some form of it the correct term 
is "endo/ecto-symbiotic" a rather contrived 
word. "Endo/ecto-symbiont" does not seem to 
have many, if any advantages over the word 

Whether the word "parasite" should be a 
synonym of "pathogen" or "not-free-living" 
or for that matter of something else is 
only of moderate interest. I have no 
objections or even concerns that the word 
will continue to be used in various ways by 
different people. It does not really matter 
what word is applied to what concept. What 
matters, of course, is that the concepts be 
clear and useful to the discipline. To me 
the importance of defining the word 
"parasite" is to explicate or to further 
understand the concept of parasite.

As I have alluded to before: If we are to 
learn anything of value from an excercise 
in defining "parasite" it should be an 
empirical endeavor. We should begin an 
explication of the concept of "parasite" 
from an examination of those things that 
parasitologists study. The common 
attributes of those organisms should form 
the initial definition. The common 
attribute, it appears to me, is the use of 
a living organism as a habitat not the 
harmful nature of the organisms.

Now, it may be appropriate to call the 
things that parasitologists study 
"endo/ecto symbionts" or for that matter 
"rutabagas." However, regardless of what we 
call them the things that parasitoligists 
study are organisms that are 
"not-free-living." That is the way that 
most parasitologists use the term in their 
work and it is this aspect of their nature 
that holds the discipline of parasitology 
together. It is what being parasitic is all 

The concern over confusion that might ensue 
by using "parasite" for "not-free-living" 
may stem from the assumption that I am 
suggesting that we change the definition of 
parasite from "pathogen" to "not 
free-living." However, "parasite" is more 
often used in the sense of 
"not-free-living" than it is as a synonym 
of "pathogen", at least among those that 
call themselves "parasitologists."

Jeffrey M. Lotz                     Phone (601) 872-4247
Gulf Coast Research Lab             Fax   (601) 872-4204
P.O. Box 7000                       Internet: jLotz at
Ocean Springs, MS 39566-7000 USA

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