Shellfish symptoms

Diarrhetic shellfish poisoning is an illness caused by polyether toxins produced by dinoflagellates and accumulated in shellfish (31). Patients suffer from diarrhea, nausea, and stomach pain but recover within three days without serious aftereffects. Despite the relatively mild symptoms, careful attention should be paid to the... 

AZP, the most-recently characterized marine seafood poisoning, is associated with eating shellfish contaminated with azaspiracids. The first human intoxications attributed to AZP occurred in the Netherlands, and the symptoms included those similar to DSP (i.e., nausea, vomiting, severe diarrhea, and stomach cramps). However, although chemical analyses did not identify significant levels of the diarrhetic shellfish poisons, they identified a new class of toxins (James et ah, 2003a). 

Using paralytic shellfish toxins extracted from mass cultures of Bay of Fundy excavata, we have found the symptoms of poisoning and the time course of their appearance to be similar in Atlantic herring, American pollock, winter flounder, Atlantic salmon, and cod (10). 

Sicherer et ah (2004) conducted a nationwide random telephone survey of the prevalence of seafood allergies in the United States and a standardized questioimaire. Responses were categorized on the basis of convincing symptoms and self-reported physician confirmation of the allergy. The survey involved 14,948 individuals with 67 reporting reactions to molluscan shellfish including scallops, clams, oysters, and mussels. The self-reported prevalence in this study population was 0.4%. 

Vitamin B12 deficiency normally results from indequate absorption rather than inadequate dietary intake. Pernicious anaemia is caused by vitamin B12 deficiency symptoms include anaemia, glossitis, fatigue and degeneration of the peripheral nervous system and hypersensitivity of the skin. The adult RDA and RNI for B12 are 2 and 1.5 figday- respectively. Unlike other vitamins, B12 is obtained exclusively from animal food sources, such as meat, fish, poultry, eggs, shellfish, milk, cheese and eggs. Vitamin B12 in these foods is protein-bound and released by the action of HC1 and pepsin in the stomach. 

Symptoms of Brevetoxins Poisoning Human Exposure to Neurotoxic Shellfish Poisoning... 

Hepatotoxicity was observed for PTX-1 and PTX-2 in some studies in which lethalities were not determined Not Determined (due to lack of dose-response curve). No symptoms reported These analogues are artifactual and have not been detected in shellfish or algae... 

Yessotoxin (YTX) was first postulated as a causative agent of severe clinical signs and symptoms of diarrhetic shellfish poisoning (DSP) (Terao et al. 1990). However, no diarrhogenic properties of this toxin have been reported (Draisci et al. 2000). The mechanism of action of YTX is not completely clarified even though several studies in this sense have been done. 

Domoic acid exposure to mammals occurs orally in a matrix of shellfish to human consumers, planktivorous fish and benthic invertebrates to marine mammals, and perhaps zooplankton and chained diatoms to whales. Analysis of the consumed mussels from the 1987 exposure indicated that 1 mg/kg was sufficient to induce gastrointestinal symptoms and 4.5 mg/kg could induce neurological effects in humans (Perl et al. 1990). Experimental studies in monkeys, rats and mice have utilized oral gavage, intraparenteal, and intravenous exposure routes and determined that oral gavage is about ten times less effective that the other routes of exposure (Iverson et al. 1990). Humans appear much more sensitive than either monkeys or rats, which when dosed orally have no observable adverse effect levels (NOAEL) at 5 and 28 mg/kg, respectively. Experimental animals have permitted evaluation of different dose scenarios. A daily NOAEL oral gavage of domoic acid to rats for... 

In 1995, a report of human illness with diarrhetic shellfish poisoning (DSP)-like symptoms in the Netherlands was eventually found to result from the consumption of poisoned mussels (Mytilus edulis) harvested from Killary Harbour, Ireland (McMahon 1996). Yasumoto, Satake, and co-workers eventually isolated and proposed a stracture for the causative agent of this condition azaspiracid-1 (la. Fig. 16.1). The unique polyether stracture of azaspiracid-1 (la) is characterized by several spiro-cyclic systems, including an azaspiro ring fused to a 2,9-dioxabicyclo[3.3.1]nonane system and a terminal carboxylic acid. In total, there are nine rings and twenty stereogenic centers within the structure proposed by Yasumoto and co-workers in 1998 (Satake 1998). This stracture was based primarily on NMR spectroscopic data and did not include absolute stereochemistry, nor did it specify relative stereochemistry between the ABCDE and FGHI domains. 

The clinical symptoms caused by azaspiracid poisoning in humans are similar to diarrhetic shellfish poisoning and to bacterial enterotoxin poisoning. Because of the similarity of the gastrointestinal symptoms induced by this new toxin and the well characterized DSP (diarrheic shellfish poisoning) toxins in humans, azaspiracids have been classified at times in the diarrheic toxin group. However, when the chemical stmcture of this new toxin was identified as a completely different molecule from DSP toxins, this toxic syndrome was named azaspiracid poisoning (AZP). 

Azaspiracid poisoning symptoms in humans include nausea, vomiting, diarrhea, stomach cramps, and headache. The symptoms appear 3 to 18 hours after eating contaminated shellfish, and the recovery is complete within 2 to 5 days (James et al. 2004 McMahon et al. 1996). 

Diagnosis of AZP in humans relies on identification of the symptoms, since there are no available laboratory tests. The only way to achieve a specific diagnosis is, if possible, to test the suspected contaminated seafood. In ai case, the specific diagnosis is not necessary for treatment since no antidote is known for shellfish toxins. The therapy is symptomatic, supported by monitoring of fluid and electrolyte levels in cases of severe intoxication. 

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