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Paratenic host?

Omar O. Barriga barriga.2 at OSU.EDU
Tue Nov 12 23:20:42 EST 1996

At 01:12 PM 11/12/96 -0500, you wrote:
>On Sat, 9 Nov 1996, Omar O. Barriga wrote:
>> I define paratenic host as that host that permits the maintenance but not the
>> development of a larval parasite. My classic example is Toxocara canis in
>> It differs from the intermediate host because it is not necessary for the 
>> cycle of the parasite. 
>The paratenic host may not be a necessary physiological step for the 
>parasite (by definition no development of the parasite occurs in a 
>paratenic host) but it is often necessary to complete the life cycle by 
>"bridging an ecological gap".
>Derek Zelmer

Dear Derek:
        I have to apologize for the typos in my previous message. I had a
connection and I was running out of time. Obviously, I was trying to type
faster than I can!
        Derek, I am not sure that I like your definition. On one hand, it
unnecessarily complicates
the concept. On the other, as soon as you say "is . . . necessary to
complete the life cycle" you 
start having problems with the differentiation with intermediate hosts. I
agree that a paratenic
host may focus the parasite toward the host (they are often part of the same
alimentary chain) 
and that may protect the parasite from the vicissitudes of the free-living
life but it has to 
have some advantage, otherwise it would not exist. I still believe that the
paratenic host is 
only an accident in the life of the parasite that happens to be convenient.
And because it is 
convenient it persists in nature.

        I'd like to continue talking (with you and other colleagues)about
this  and other subjects 
of parasite biology that are open to personal interpretations. 

        Have a great day!

                                        Omar O. Barriga

Omar O.Barriga, DVM, PhD
The Ohio State University
1900 Coffey Road
Columbus, Ohio 43210, USA
Phone 614-292-1206
Fax   614-293-4142
E-mail barriga.2 at osu.edu

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