Baylisascaris and raccoons

Irisnbob irisnbob at aol.com
Wed Jul 8 23:45:57 EST 1998


I did my M.S. degree with Dr. Kazacos at Purdue and have seen my share of B.
procyonis eggs, so I might be able to help.  I'm curious about your statement
that a flotation will not give you a definitive diagnosis.  Technically, one
could argue that the only way to be 100% certain that the eggs are B. procyonis
is to identify the worm, but realistically, it's not necessary nor is it done
routinely.  For diagnostic parasitology purposes, and certainly for a science
education project, finding eggs that match the description of B. procyonis in
the feces of a raccoon is definitive enough.  The only Baylisascaris spp.
you'll find in a coon is B. procyonis.

As a reference (sorry, I can't send a copy) I would suggest the paper
"Baylisascaris larva migrans" by Kazacos and Boyce, Journal of the American
Veterinary Medical Association, 195:894-904, 1989.  This is the one paper I
would recommend to anyone who wants the "big picture" about B. procyonis.  It
shows a clear photo of an egg and lists its dimensions.

I have no idea what your project is, but from a public health standpoint, I
would STRONGLY discourage you from using the eggs of this parasite as part of a
science education project.  (Avoiding ascarid parasites altogether would be a
good idea.)  I don't mean to sound condescending and I apologize in advance if
I do, but unless you have the equipment, facilities and knowledge to handle B.
procyonis eggs safely, you're playing with fire.  The eggs are harmless in
freshly passed raccoon scat, but once they become larvated (about 3 weeks or
less in Texas summer weather), they are capable of causing catastrophic human
illness if sufficient numbers are accidentally ingested (and very little can be
done for persons so afflicted).  Smaller numbers, such as might be found on the
stage of a microscope which wasn't decontaminated, are thought to be capable of
causing serious ocular problems.  

Hope this is of some help--

Bob Garrison, DVM, MS



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