Published Date: 2010-07-14 10:00:09
Subject: PRO/AH/EDR> Paralytic shellfish poisoning - USA: (ME) warning
Archive Number: 20100714.2353
PARALYTIC SHELLFISH POISONING - USA: (MAINE) WARNING
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
Date: Fri 9 Jul 2010
Source: Maine Public Broadcasting Network (MPBN) [edited]
Maine red tide outbreak prompts shellfish warning
The toxic algal blooms are affecting shellfish beds in Maine, from
Cutler to the Canadian border.
As red tide hits the Maine coast, state health officials are urging
people to make sure they consume seafood safely. The toxic algal
blooms have led to closures of shellfish beds in Maine, from Cutler
to the Canadian border. The toxin can contaminate shellfish and
sicken people who eat them, sometimes fatally, officials say.
Maine Center for Disease Control officials say shellfish purchased
from a licensed dealer is safe to eat because their operations
undergo rigorous screening and auditing. Those harvesting shellfish
for their own personal use should make sure the shellfish beds are
not closed due to red tide. Information on which beds are closed can
be found online at
Officials say people should never eat clams or mussels floating in
ocean waters because they're likely to be contaminated with much more
of the red tide toxin than those in beds. And when eating lobster,
they say, don't eat the tomalley, the green material in the body
cavity, which serves as the lobster's liver. The lobster meat is safe to eat.
State health officials say 3 incidents of so-called paralytic
shellfish poisoning have occurred in Downeast Maine over the past
years, sickening a total of 8 people, none of them fatally. In all 3
cases, people had harvested mussels for personal use, in one case
from a closed area.
HealthMap Alerts via ProMED-mail
["Red tide is caused by several toxic algae. Depending upon the
toxin, it is also known as paralytic shellfish poisoning (PSP),
because it causes shellfish to be toxic for consumption.
PSP is a significant problem in several geographic areas, especially
in both the east and the west coasts of the US. Produced 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
_Alexandrium_ blooms generally do not involve large-cell
accumulations that discolor the water and may instead be invisible
below the water surface. Low-density populations can cause severe
problems due to the high potency of the toxins produced. 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 strategies.
Often PSP is associated with red tides or algal blooms. Red tide is
caused by an organism called _Karenia brevis_, which in high
concentrations 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 several days.
Previously the organism causing red tide was known as _Gymnodinium
breve_, but it 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.
The red tide update website is at
This moderator comment was borrowed from prior postings such as
Paralytic shellfish poisoning - South Africa (W. Cape): red tide
20070325.1039). - Mod.TG]
[The HealthMap/ProMED-mail interactive map of the state of Maine in
the northeastern US is available at
<http://healthmap.org/r/01J7>. - Sr.Tech.Ed.MJ