paralytic shellfish toxin?

David Clopton dclopton at
Sat May 14 02:39:38 EST 1994

In <CpIHvM.DzE at> muriana at (Peter M. Muriana) writes:

>In article <Pine.3.05.9405081400.A13626-a100000 at>,
> guia at CC.UManitoba.CA (Antonio Guia) writes:
>>On Fri, 6 May 1994, Peter M. Muriana wrote:
>>>I'm drawing on memory here but I recall that paralytic shellfish toxin is due 
>>> to saxitoxin produced by certain dinoflagellates (Gonyaulax tamaerensis?).  
>>Maybe i have gotten the name of the disease wrong, but i was convinced
>>that it was domoic acid and that an antidote has been found to be kainic

>I believe domoic acid and kainic acid are *both* toxic amino acids produced
>by marine sources; domoic acid from a marine diatom, Nitzschia pungens,which
>can contaminate mussels.  The saxitoxin that I mentioned above, together 
>with a number of other closely related neurotoxins (neosaxitoxin, 
>gonyautoxin I, II, III, IV, and others) are responsible for the syndrome
>called "paralytic shellfish poisoning", are produced by several planktonic 

	This whole area gets rather confusing for someone just
looking into one aspect.  There is "paralytic shellfish poisoning,"
which is produced by a whole group of dinoflagellate species.  There
is, I gather, still some arguments going on about exactly how to
classify all of them.  Seems like the latest I remember is that the
PSP-producing species are to be included in the genus Alexandrium.
Includes the "former" Gonyaulax tamarensis mentioned above.
These produce saxitoxins, and so on, as Peter enumerated.
	Then there is diarrheic shellfish poisoning, which hasn't
been a problem in the US that we know of.  This is caused by okadaic
acid producing dinoflagellates.
	Domoic acid leads to amnesiac shellfish poisoning, and is
produced, as Peter said, by N. pungens, and also by P. australis.
It caused problems in Canada several years back, and also was
responsible for the mass pelican (in particular) kill in the
Monterrey Bay area of California a few years ago.  I think I've seen
that there is some evidence that some of the clams (Razor springs to
mind, but I am not certain) in the northwest may accumulate domoic
	The short form for the initial question is that the local
health authorities probably sample from time to time and will make
an announcement to close shellfish beds.  You just need to watch for
it, or call.  Souther California does that, precisely to avoid the
problem of people picking their own and having problems.  I THINK I
remember them "closing" the shellfish beds recently.
	So what you should probably tell your friend is that he
should check with the local public health people.  Yes, he certainly
could have problems - shellfish contamination is a problem that
seems to be on the increase.  I can't remember Puget Sound's status
off the top of my head, so they must not have had any MAJOR

	David Clopton
	dclopton at
	"All std. disclaimers apply"


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