Published Date: 2002-09-14 23:50:00
Subject: PRO/AH> Paralytic shellfish poisoning - Canada (NB)
Archive Number: 20020914.5303
PARALYTIC SHELLFISH POISONING - CANADA (NEW BRUNSWICK)
A ProMED-mail post
ProMED-mail, a program of the
International Society for Infectious Diseases
Date: Thu 12 Sep 2002
From: ProMED-mail <email@example.com>
Source: Canoe.com / CP, [Wed 11 Sep 2002] [edited]
Toxin outbreak leads to DFO ban on shellfish harvesting in Red Head, N.B.
An increase in levels of paralytic shellfish poison has led to the
immediate closure of all shellfish harvesting in the Bay of Fundy around
Ron Smith, a Department of Fisheries and Oceans spokesman in Halifax, said
Wednesday the closure affects clams, mussels, quahogs and other mollusks.
[Paralytic shellfish poisoning (PSP) is a significant problem in several
geographic areas, especially on both the east and west coasts of the U.S.
Caused by several closely related species in the genus _Alexandrium_, PSP
toxins are responsible for persistent problems due to their accumulation in
filter-feeding shellfish, but they also move through the food chain,
affecting zooplankton, fish larvae, adult fish, and even birds and marine
_Alexandrium_ blooms generally do not involve large-cell accumulations that
discolor the water and may be below the water surface where they are not
visible. Low-density populations can cause severe problems due to the high
potency of the toxins produced by these species. Furthermore, _Alexandrium_
spp. can grow in relatively pristine waters, and it is difficult to argue
that anthropogenic nutrient inputs are stimulating the blooms. These
characteristics are important when considering mitigation and control
Often PSP is associated with red tides or algal blooms. Red tide is caused
by an organism called _Karenia brevis_, which in high concentration can
make the water look red. The organism releases a toxin that paralyzes the
respiratory system of fish and other marine life.
Airborne toxins, water spray, and splashes in an outbreak have kept people
from beaches while leaving others with irritated eyes and throats. Red tide
irritates the skin of people exposed to it and can cause itchy eyes,
scratchy throats, and coughs.
Harvesting from affected areas for personal consumption is discouraged. Red
tide poisoning symptoms include nausea and dizziness and may last for
Previously red tide was known as _Gymnodinium breve_ and has been
reclassified in the taxonomy of dinoflagellates. Its new name is _Karenia
brevis_, or _K. brevis_. Karenia was chosen in honor of Dr. Karen
Steidinger, a prominent red tide scientist from the Florida Marine Research
Institute in St. Petersburg, FL.