Marie Celine C. Makinano III – A

Red Tide (Paralytic Shellfish Poisoning)

Description : What is Red Tide?

Red Tide is caused by a "population explosion" of toxic, naturally occurring microscopic plankton (specifically, a subgroup known as dinoflagellates). "Blooms" of the poison-producing plankton are coastal phenomena caused by environmental conditions, which promote explosive growth. Factors that are especially favorable include warm surface temperatures, high nutrient content, low salinity, rainy days followed by sunny weather and calm seas. Rain followed by sunny weather in the summer months is often associated with red tide blooms.

Etiologic AgentThe marine red tide organisms used to be referred to as Gonyaulax, Protogonyaulax,

Alexandrium and Gessnerium. Presently, they are known by the accepted name Alexandrium species. Organisms that cause theses blooms around the United States are as follows:

Alexandrium fundyense (formerly A. Tamarense), along the Atlantic Northeast coast, ranging from the Canadian Maritimes to Southern New England;

Alexandrium Catenella, on the Pacific West Coast from California to Alaska; and

Karonia brevis (formerly Ptychodiscus brevis), in the Gulf of Mexico along the West Florida coast.

Does it really color the water?

Yes. Water in the coastal areas can be colored red by the algae, thus, the term Red Tide. The toxic blooms often turn the water reddish-brown although there are some algae that are not poisonous. Conversely, toxic plankton maybe numerous enough to toxify shellfish but not sufficient enough to discolor water.

Certain kinds of seafood from water with Red Tide are unsafe to eat. Shellfish are particularly prone to contamination as they feed by filtering microscopic food out of the water. If toxic planktonic organisms are present, they are filtered from the water along with their non-toxic food.

Pathophysiology

What happens if toxic shellfish are consumed?

Eating toxic shellfish can cause paralytic shellfish poisoning (PSP) in humans. PSP is caused by saxitoxin, which is produced by Alexandrium fundyense and is one of the most potent toxins known to scientists. After ingestion, this poison immediately affects the nervous system, with symptoms usually occurring within 30 minutes. Severity depends on the amount of toxin consumed. Initial reactions are tingling of the lips and tongue, which spreads to the face, neck, fingertips and toes. Headache, dizziness and

nausea follow. These symptoms may be mistaken for drunken conditions and are further aggravated by alcohol consumption. In severe cases, muscular paralysis and respiratory difficulty may occur within 5 to 12 hours. Fatalities from respiratory paralysis have been reported.

Red Tide is caused by a "population explosion" of toxic, naturally occurring microscopic plankton (specifically, a subgroup known as dinoflagellates).

Toxic Shellfish consumed

Alexandrium fundyense produces Paralytic Shellfish PoisoningSaxitoxin, potent toxin known

Nervous system is then affected, with signs and symptoms shown after 30 minutes

tingling of the lips and tongue, which spreads to the face, neck, fingertips and toes. Headache, dizziness and nausea follow

In severe cases, muscular paralysis and respiratory difficulty may occur within 5 to 12 hours. Fatalities from respiratory paralysis have been reported.

Signs and Symptoms

Symptoms from breathing red tide toxins are normally coughing, sneezing and teary eyes. Symptoms are usually temporary when red tide toxins are in the air. Wearing a particle filter mask may lessen the effects, and research shows that using over-the-counter antihistamines may decrease your symptoms. Check the marine forecast. Fewer toxins are in the air when the wind is blowing offshore.

Initial reactions are tingling of the lips and tongue, which spreads to the face, neck, fingertips and toes.

Headache, dizziness and nausea follow. These symptoms may be mistaken for drunken conditions

Such symptoms are further aggravated by alcohol consumption.

Complications

In severe cases, muscular paralysis and respiratory difficulty may occur within 5 to 12 hours. Fatalities from respiratory paralysis have been reported.

Amnesic shellfish poisoning is most common in the Pacific Northwest. The unfortunate consumer of the bad shellfish will first experience "normal" symptoms of seafood poisoning, but may soon become confused, disoriented and even comatose. The cognitive damage is permanent, affecting short-term memory and even causing dementia.

Different Periods

According to Long Island Sound Study, A. fundyense has formed toxic blooms in the Gulf of Maine every year (Anderson et al. 2005 and references therein). In recent years, its bloom extended southward, with severe toxic outbreaks occurring along the south shore of Long Island Sound in 2008 (http://www.longislandsoundstudy.net/newsmail/june_08_onlinev.htm). This species was detected in the bait-worm packaging throughout the study period, with higher occurrence in July and August 2008 corresponding with a PSP outbreak on August 1, 2008 that eventually closed Maine’s shellfish beds (Fitzpatrick 2008). Although it is unclear how A. fundyense was introduced into LIS, our results indicate that bait worm products are a potential vector. It is interesting to note that the most severe bloom in LIS has occurred in Northport Harbor where fishing has been very active. Diagnostic Tests

1. A recently developed commercial rapid test kit (MIST Alert or Maritime In Vitro Shellfish Test) was assessed for determination of the presence of paralytic shellfish poisoning (PSP) toxins in shellfish. Several commercially important shellfish species obtained from the UK shellfish toxin monitoring program, containing a range of total PSP toxicities as determined by the mouse bioassay (MBA), were tested. The kit detected toxin in all samples containing the European Community tolerance level of 80 μg saxitoxin (STX) equivalents/100 g shellfish flesh as determined by the MBA. With one exception, the kit detected toxin in all samples that contained >40 μg STX equivalents/100 g according to the MBA. Among samples in which the MBA did not detect toxin, the kit disagreed in 25% of the tests, although further analysis by liquid chromatography (LC) and MBA of some samples confirmed the presence of toxins.

These results suggest that MIST Alert may be suitable as an initial screen for PSP toxins as part of routine monitoring programs, thereby greatly reducing the number of MBAs. Trials were also performed by nonscientific personnel to evaluate the ease of use and interpretation of results obtained by MIST Alert. The results indicated that the kits could be readily used and accurately interpreted by individuals with no technical or scientific background.

Key benefits: fast, accurate, yes/no results within 20 minutes detects all toxin analogues

shelf life of 1 year

cost effective

user friendly

permanent record

durable for field work

eliminates animal use

2. AOAC mouse bioassay. The procedure was developed more than half a century ago and has been refined and standardized by the Association of Official Analytical Chemists (AOAC) to produce a rapid and reasonable accurate measurement of total PSP toxins (Hollingworth and Wekell, 1990). Twenty gram mice are injected with 1 ml of an acid extract of the shellfish and the time taken for the animal to die is recorded. Highly toxic extracts are diluted to ensure that mortality occurs within 5 to 15 minutes. The toxicity of the sample is then calculated with reference to dose response curves established with STX standards and expressed in mouse units (MU). In most countries the action level for closure of the fishery is 400 MU/100 g shellfish (1 MU is the amount injected toxin which would kill a 20 g mouse in 15 minutes and is equivalent to 0.18 mg of STX). The limit of detection of the assay is approximately 40 µg STX/100g of shellfish tissue with a precision of ± 15-20 percent. A known interference is a high salt content of samples which suppresses toxic effects (Schantz et al., 1958), whereas zinc accumulation in oysters has been reported to lead to lethal effects in mice at levels that present no health threat to humans (Aune et al., 1998).

Different Treatments

Procedures

o Charcoal hemoperfusion is a process done by pumping the arterial blood through an activated charcoal filter to remove the poison.

Medications

o Antihistamines may decrease symptoms.o Alkaline fluids, such as sodium bicarbonate are thought to be helpful because toxin is

unstable in alkaline condition.

Nursing Management

o Induce patient/client to vomit.o Artificial respiration is required if patient exhibits respiratory stress.o Discolored water should always be regarded with suspicion. o Wearing a particle filter mask may lessen the effects, and research shows that giving of

over-the-counter antihistamines may decrease symptoms.o Watch what client eats. Avoid seafood especially shellfish such as: quahogs, soft shell

clams, oysters, mussels, scallops and moon snail. Inform client that cooking does not destroy the organisms.

o Lobster, crabs, shrimps and fish do not accumulate toxin and are safe to eat even if they are from affected water.

o Instruct client that if accidental ingestion of toxic shellfish is suspected, seek medical attention immediately.

Pictures

Sources: http://www.mass.gov/?

pageID=eohhs2modulechunk&L=4&L0=Home&L1=Provider&L2=Guidance+for+Businesses&L3=Food+Safety&sid=Eeohhs2&b=terminalcontent&f=dph_environmental_foodsafety_p_red_tide&csid=Eeohhs2

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2006, C & E Publishing, Inc., pg. 203-2006 http://longislandsoundstudy.net/wp-content/uploads/2010/02/Yarish.summary.20-Jan-

09.pdf

http://health.howstuffworks.com/wellness/food-nutrition/facts/shellfish-r- months.htm/printable