Use of intravenous lipid emulsion therapy as a novel treatment for brevetoxicosis in sea turtles

The southwest coast of Florida experiences annual red tides, a type of harmful algal bloom that results from high concentrations of Karenia brevis. These dinoflagellates release lipophilic neurotoxins, known as brevetoxins, that bind to sodium channels and inhibit their inactivation, resulting in a variety of symptoms that can lead to mass sea turtle strandings. Traditional therapies for brevetoxicosis include standard and supportive care (SSC) and/or dehydration therapy; however, these treatments are slow-acting and often ineffective. Because red tide events occur annually in Florida, our objective was to test intravenous lipid emulsion (ILE) as a rapid treatment for brevetoxicosis in sea turtles and examine potential impacts on toxin clearance rates, symptom reduction, rehabilitation time, and survival rates. Sea turtles exhibiting neurological symptoms related to brevetoxicosis were brought to rehabilitation from 2018-2019. Upon admission, blood samples were collected, followed by immediate administration of 25 mg ILE/kg body mass (Intralipid® 20%) at 1 mL/min using infusion pumps. Blood samples were collected at numerous intervals post-ILE delivery and analyzed for brevetoxins using enzyme-linked immunosorbent assays. In total, nine (four subadults, one adult female, four adult males) loggerheads (Caretta caretta), five (four juvenile, one adult female) Kemp's ridleys (Lepidochelys kempii), and four juvenile green turtles (Chelonia mydas) were included in this study. We found that plasma brevetoxins declined faster compared to turtles that received only SSC. Additionally, survival rate of these patients was 94% (17/18), which is significantly higher than previous studies that used SSC and/or dehydration therapy (47%; 46/99). Nearly all symptoms were eliminated within 24-48 h, whereas using SSC, symptom elimination could take up to seven days or more. The dosage given here (25 mg/kg) was sufficient for turtles in this study, but the use of a higher dosage (50-100 mg/kg) for those animals experiencing severe symptoms may be considered. These types of fast-acting treatment plans are necessary for rehabilitation facilities that are already resource-limited. Intravenous lipid emulsion therapy has the potential to reduce rehabilitation time, save resources, and increase survival of sea turtles and other marine animals experiencing brevetoxicosis.

Investigating the gene expression profiles of rehabilitated Florida manatees (Trichechus manatus latirostris) following red tide exposure

To investigate a Florida manatee (Trichechus manatus latirostris) mortality event following a red tide bloom in Southwest Florida, an RNA sequencing experiment was conducted. Gene expression changes in white blood cells were assessed in manatees rescued from a red tide affected area (n = 4) and a control group (n = 7) using RNA sequencing. The genes with the largest fold changes were compared between the two groups to identify molecular pathways related to cellular and disease processes. In total, 591 genes (false discovery rate <0.05) were differentially expressed in the red tide group. Of these, 158 were upregulated and 433 were downregulated. This suggests major changes in white blood cell composition following an exposure to red tide. The most highly upregulated gene, Osteoclast associated 2C immunoglobulin-like receptor (OSCAR), was upregulated 12-fold. This gene is involved in initiating the immune response and maintaining a role in adaptive and innate immunity. The most highly downregulated gene, Piccolo presynaptic cytomatrix protein (PCLO), was downregulated by a factor of 977-fold. This gene is associated with cognitive functioning and neurotransmitter release. Downregulation of this gene in other studies was associated with neuronal loss and neuron synapse dysfunction. Among the cellular pathways that were most affected, immune response, including inflammation, wounds and injuries, cell proliferation, and apoptosis were the most predominant. The pathway with the most differentially expressed genes was the immune response pathway with 98 genes involved, many of them downregulated. Assessing the changes in gene expression associated with red tide exposure enhances our understanding of manatee immune response to the red tide toxins and will aid in the development of red tide biomarkers.

[Scombroid food poisoning among hospital personnel]

BACKGROUND

Scombroid food poisoning is caused by eating fish with a high concentration of histamine. Histamine is converted from histidine in fish of the Scombroidea family if it is not stored at a sufficiently low temperature. The clinical picture resembles an allergic reaction.

CASE DESCRIPTION

Twenty-one of our hospital personnel went to the ER, mostly reporting flushing, headache, palpitations and gastro-intestinal symptoms. They had all eaten tuna salad in the staff canteen. The symptoms appeared to be caused by scombroid food poisoning.

CONCLUSION

As a result of early recognition of the clinical picture and prompt crisis management we were able to prevent the outbreak spreading further.

Identification and management of marine envenomations in pediatric patients

Marine envenomations can cause a diverse array of clinical syndromes. Systemic and life-threatening reactions, as well as delayed presentations, can occur. The pediatric population is at higher risk for serious reactions to envenomations because their greater body surface area and smaller body mass can lead to a higher relative venom load. Although the majority of the literature on marine envenomations is of low quality, the available literature does suggest that management varies depending on the geographic location. This issue reviews both common and life-threatening presentations of marine envenomations, highlights key aspects of the history and physical examination that will help narrow the differential, and offers recommendations for management based on the envenomating creature and geographic location.

Fluorescent immunoliposomal nanovesicles for rapid multi-well immuno-biosensing of histamine in fish samples

Scombroid poisoning in fish-based and other food products has raised concerns due to toxicity outbreaks and incidences associated with histamine, thus measuring the amount of histamine toxic molecule is considered crucial quality indicator of food safety and human health. In this study, liposome-based measurement of histamine was performed via rupturing mechanism of sulforhodamine B dye encapsulated anti-histamine antibody conjugated liposomal nanovesicles. The immunosensing ability of immuno-liposomal format was assessed by monitoring the fluorescence at excitation/emission wavelength of 550/585 nm. Immuno-liposomal format assays were considered, one based on single wash procedure (Method 1), which had a detection limit of 10 ppb and quantification limit 15-80 ppb. While Method 2 based on one-by-one wash procedure had a detection limit of 2-3 ppb and quantification limit 8.5 ppb-200 ppm that required 2 h 30 min to perform. In view of better quantification limit, Method 2 was chosen for further tests required to validate its applicability in real samples. The feasibility of Method 2 was reconfirmed in fresh mackerel fish, and canned fish (tuna and salmon) with a similar detection limits but with low amplified fluorescence signals and sufficient levels of histamine recovery from fresh mackerel (73.50-99.98%), canned tuna (79.08-103.74%) and salmon (74.56-99.02%). The specificity and method accuracy were expressed as % CV in the range 5.34%-8.48%. Overall, the developed multi-well sensing system (Method 2) showed satisfactory specificity, cost effectiveness, rapidity, and stability for monitoring histamine toxicity as a practical food diagnostic device.

Mixtures of Lipophilic Phycotoxins: Exposure Data and Toxicological Assessment

Lipophilic phycotoxins are secondary metabolites produced by phytoplanktonic species. They accumulate in filter-feeding shellfish and can cause human intoxication. Regulatory limits have been set for individual toxins, and the toxicological features are well characterized for some of them. However, phycotoxin contamination is often a co-exposure phenomenon, and toxicological data regarding mixtures effects are very scarce. Moreover, the type and occurrence of phycotoxins can greatly vary from one region to another. This review aims at summarizing the knowledge on (i) multi-toxin occurrence by a comprehensive literature review and (ii) the toxicological assessment of mixture effects. A total of 79 publications was selected for co-exposure evaluation, and 44 of them were suitable for toxin ratio calculations. The main toxin mixtures featured okadaic acid in combination with pectenotoxin-2 or yessotoxin. Only a few toxicity studies dealing with co-exposure were published. In vivo studies did not report particular mixture effects, whereas in vitro studies showed synergistic or antagonistic effects. Based on the combinations that are the most reported, further investigations on mixture effects must be carried out.

Acute and chronic dietary exposure to domoic acid in recreational harvesters: A survey of shellfish consumption behavior

Domoic acid (DA) is a neurotoxin that is naturally produced by phytoplankton and accumulates in seafood during harmful algal blooms. As the prevalence of DA increases in the marine environment, there is a critical need to identify seafood consumers at risk of DA poisoning. DA exposure was estimated in recreational razor clam (Siliqua patula) harvesters to determine if exposures above current regulatory guidelines occur and/or if harvesters are chronically exposed to low levels of DA. Human consumption rates of razor clams were determined by distributing 1523 surveys to recreational razor clam harvesters in spring 2015 and winter 2016, in Washington, USA. These consumption rate data were combined with DA measurements in razor clams, collected by a state monitoring program, to estimate human DA exposure. Approximately 7% of total acute exposures calculated (including the same individuals at different times) exceeded the current regulatory reference dose (0.075mgDA·kgbodyweight^-1·d^-1) due to higher than previously reported consumption rates, lower bodyweights, and/or by consumption of clams at the upper range of legal DA levels (maximum 20mg·kg^-1 wet weight for whole tissue). Three percent of survey respondents were potentially at risk of chronic DA exposure by consuming a minimum of 15 clams per month for at 12 consecutive months. These insights into DA consumption will provide an additional tool for razor clam fishery management.

Domoic Acid Poisoning as a Possible Cause of Seasonal Cetacean Mass Stranding Events in Tasmania, Australia

The periodic trend to cetacean mass stranding events in the Australian island state of Tasmania remains unexplained. This article introduces the hypothesis that domoic acid poisoning may be a causative agent in these events. The hypothesis arises from the previously evidenced role of aeolian dust as a vector of iron input to the Southern Ocean; the role of iron enrichment in Pseudo-nitzschia bloom proliferation and domoic acid production; and importantly, the characteristic toxicosis of domoic acid poisoning in mammalian subjects leading to spatial navigation deficits. As a pre-requisite for quantitative evaluation, the plausibility of this hypothesis was considered through correlation analyses between historical monthly stranding event numbers, mean monthly chlorophyll concentration and average monthly atmospheric dust loading. Correlation of these variables, which under the domoic acid stranding scenario would be linked, revealed strong agreement (r = 0.80-0.87). We therefore advocate implementation of strategic quantitative investigation of the role of domoic acid in Tasmanian cetacean mass stranding events.

The role of ions, heavy metals, fluoride, and agrochemicals: critical evaluation of potential aetiological factors of chronic kidney disease of multifactorial origin (CKDmfo/CKDu) and recommendations for its eradication

The pollution of water and food through human waste and anthropogenic activities, including industrial waste and agricultural runoff, is a mounting problem worldwide. Water pollution from microbes causes identifiable diarrhoeal illnesses. The consumption of water contaminated with heavy metals, fluoride, and other toxins causes insidious illnesses that lead to protracted, non-communicable diseases and death. Chronic kidney disease of unusual/uncertain/unknown aetiology is one such example, began to manifest in the mid-1960s in several dry-zonal agricultural societies in developing economies that are located around the equator. In Sri Lanka, such a disease is affecting the North Central Province, the rice bowl of the country that first appeared in the mid-1990s. Several potential causes have been postulated, including heavy metals, fluoride, cyanobacterial and algae toxins, agrochemicals, and high salinity and ionicity in water, but no specific source or causative factor has been identified for CKD of multifactorial origin (CKDmfo). Three large studies conducted in the recent past failed to find any of the postulated components (heavy metals, cyanobacterial toxins, fluoride, salinity, or agrochemicals) at levels higher than those deemed safe by the World Health Organization and the US Environmental Protection Agency. At the reported low levels in water and with the heterogeneous geographical distribution, it is unrealistic to expect any of these components individually could cause this disease. However, the additive or synergistic effects of a combination of factors and components, even at lower exposure levels, together with malnutrition and harmful behaviours, and/or a yet-unidentified (or not investigated) toxin, can cause this epidemic. Because the cause is unknown, scientists need to work on broader hypotheses, so that key causative elements are not missed. Taken together the plausibility of multiple factors in the genesis of this disease, the appropriate terminology is CKDmfo, a name that also indicates the need for multi-disciplinary research programs to facilitate identifying the cause(s) and the need for multiple approaches to eradicate it. While some potential causes remain to be investigated, existing data point to polluted water as the main source of this disease. This article evaluates pros and cons of each hypothesis and highlights the importance of among others, providing clean water to all affected and surrounding communities. Available data do not support any of the postulated agents, chemicals, heavy metals, fluoride, salinity/ionicity, or individual agrochemical components, such as phosphate or glyphosate, as causative factors for CKDmfo in Sri Lanka. However, as the CKDmfo name implies, a combination of these factors (or an unknown toxin) together with harmful behaviour and chronic dehydration may cause this disease. Irrespective of the cause, prevention is the only way forward for eradication.

Palytoxin-Containing Aquarium Soft Corals as an Emerging Sanitary Problem

Palytoxin (PLTX), one the most potent marine toxins, and/or its analogs, have been identified in different marine organisms, such as Palythoa soft corals, Ostreopsis dinoflagellates, and Trichodesmium cyanobacteria. Although the main concern for human health is PLTXs entrance in the human food chain, there is growing evidence of adverse effects associated with inhalational, cutaneous, and/or ocular exposure to aquarium soft corals contaminated by PLTXs or aquaria waters. Indeed, the number of case reports describing human poisonings after handling these cnidarians is continuously increasing. In general, the signs and symptoms involve mainly the respiratory (rhinorrhea and coughing), skeletomuscular (myalgia, weakness, spasms), cardiovascular (electrocardiogram alterations), gastrointestinal (nausea), and nervous (paresthesia, ataxia, tremors) systems or apparates. The widespread phenomenon, the entity of the signs and symptoms of poisoning and the lack of control in the trade of corals as aquaria decorative elements led to consider these poisonings an emerging sanitary problem. This review summarizes literature data on human poisonings due to, or ascribed to, PLTX-containing soft corals, focusing on the different PLTX congeners identified in these organisms and their toxic potential.

Don't be Half-Educated About Haff Disease in Louisiana

Cases of Haff disease, a syndrome of severe myalgia and rhabdomyolysis, have been reported after eating cooked fish in Europe and the US. A retrospective review of US cases was conducted to identify seafood vectors, describe presenting manifestations, and compare the Haff disease toxidrome with other seafood-borne toxidromes. Internet search engines were queried to identify all US reports of Haff disease. The case definition of Haff disease required cooked seafood ingestion history within 24 hours and markedly elevated serum creatine kinase (CK) with CK-muscle/brain (MB) fraction < 5 percent. Twenty-six cases of Haff disease were reported in the US over 30 years, 1984-2014, with spring-summer occurrences. The mean age of cases was 54.8 years without gender difference. Most cases (58 percent) followed consumption of cooked buffalo fish, Ictiobus cyprinellus, (n = 15); other cases followed consumption of boiled crayfish in Louisiana (n = 9) and baked salmon in North Carolina (n = 2). California and Louisiana accounted for most cases (n = 18, p = 0.012). Following mean incubation periods of eight hours; the most common presenting manifestations included vomiting, myalgia, muscle rigidity, chest pain mimicking myocardial infarction, diaphoresis, dyspnea, and brown urine indicating myoglobinuria. Most patients recovered within 2-5 days. Haff disease may follow the consumption of freshwater buffalo fish, freshwater crayfish, and saltwater Atlantic salmon. The bioconcentration of a new, unidentified heat-stable, freshwater and/or brackish/saltwater algal myotoxin in seafood, similar to palytoxin, is suspected of causing Haff disease. Experimental animals fed toxic buffalo fish developed rhabdomyolysis with myoglobinuria.

Simultaneous determination of biotoxins DSP and AZAs in bivalve molluscs and fish by liquid chromatography/tandem mass spectrometry

RATIONALE

A method has been developed for simultaneous determination of the toxins OA, DTX-1, AZA-1, AZA-2 and AZA-3 in various aquatic products as these can cause diarrhoetic shellfish poisoning (DSP) in humans, an intoxication characterized by vomiting and diarrhea.

METHODS

Separation of the toxins was achieved on a C18 column (150 mm × 2.1 mm, 3.5 µm) using an acetonitrile/water gradient with formic acid as an eluent modifier. Electrospray ionisation (ESI) in negative mode was used to generate the molecule related ion [M-H](-), for OA and DTX-1, while ESI in positive mode was used to generate the molecule related ion [M+H](+) for AZAs. Samples were extracted with 80% methanol, followed by partitioning with ethyl acetate, purified on a Poly-Sery MAX cartridge and finally analyzed by LC/ESI-MS/MS in the multiple reaction monitoring (MRM) mode.

RESULTS

The limit of detection (LOD) and limit of qualification (LOQ) of the method were in the range of 0.02-0.79 µg/kg and 0.07-2.64 µg/kg in Scomberomorus niphonius, blood clam and oyster, respectively, recoveries of the toxins at three fortification levels ranged from 71.3% to 104.8% with relative standard deviation from 1.0% to 12.5%. The calibration curves were well linear between the LC peak area of the selected ion pair and the concentration of the toxins, with the correlation coefficient over 0.99.

CONCLUSIONS

The method was sufficiently sensitive to permit the determination of the toxins DSP and AZA in sea food.

[Problems caused by poisonous tropical marine animals]

A Finnish physician encounters problems caused by tropical marine animals either during her/his own travelling or while treating travelers who have returned home. Certain species of medusae and cone shells as well as the stings by some fish species are life-threateningly poisonous. A person stung or bitten by any of the most dangerous species must immediately be admitted to the hospital. Foreign material remaining in tissues after stings by echinoderms and spiky fish may cause problems months after the actual injury. The injuries become easily infected, and antimicrobial drug therapy must thus cover gram-negative rod-shaped bacteria as well.

Risk assessment of shellfish toxins

Complex secondary metabolites, some of which are highly toxic to mammals, are produced by many marine organisms. Some of these organisms are important food sources for marine animals and, when ingested, the toxins that they produce may be absorbed and stored in the tissues of the predators, which then become toxic to animals higher up the food chain. This is a particular problem with shellfish, and many cases of poisoning are reported in shellfish consumers each year. At present, there is no practicable means of preventing uptake of the toxins by shellfish or of removing them after harvesting. Assessment of the risk posed by such toxins is therefore required in order to determine levels that are unlikely to cause adverse effects in humans and to permit the establishment of regulatory limits in shellfish for human consumption. In the present review, the basic principles of risk assessment are described, and the progress made toward robust risk assessment of seafood toxins is discussed. While good progress has been made, it is clear that further toxicological studies are required before this goal is fully achieved.

Okadaic acid: more than a diarrheic toxin

Okadaic acid (OA) is one of the most frequent and worldwide distributed marine toxins. It is easily accumulated by shellfish, mainly bivalve mollusks and fish, and, subsequently, can be consumed by humans causing alimentary intoxications. OA is the main representative diarrheic shellfish poisoning (DSP) toxin and its ingestion induces gastrointestinal symptoms, although it is not considered lethal. At the molecular level, OA is a specific inhibitor of several types of serine/threonine protein phosphatases and a tumor promoter in animal carcinogenesis experiments. In the last few decades, the potential toxic effects of OA, beyond its role as a DSP toxin, have been investigated in a number of studies. Alterations in DNA and cellular components, as well as effects on immune and nervous system, and even on embryonic development, have been increasingly reported. In this manuscript, results from all these studies are compiled and reviewed to clarify the role of this toxin not only as a DSP inductor but also as cause of alterations at the cellular and molecular levels, and to highlight the relevance of biomonitoring its effects on human health. Despite further investigations are required to elucidate OA mechanisms of action, toxicokinetics, and harmful effects, there are enough evidences illustrating its toxicity, not related to DSP induction, and, consequently, supporting a revision of the current regulation on OA levels in food.

Canine cyanotoxin poisonings in the United States (1920s-2012): review of suspected and confirmed cases from three data sources

Cyanobacteria (also called blue-green algae) are ubiquitous in aquatic environments. Some species produce potent toxins that can sicken or kill people, domestic animals, and wildlife. Dogs are particularly vulnerable to cyanotoxin poisoning because of their tendency to swim in and drink contaminated water during algal blooms or to ingestalgal mats.. Here, we summarize reports of suspected or confirmed canine cyanotoxin poisonings in the U.S. from three sources: (1) The Harmful Algal Bloom-related Illness Surveillance System (HABISS) of the National Center for Environmental Health (NCEH), Centers for Disease Control and Prevention (CDC); (2) Retrospective case files from a large, regional veterinary hospital in California; and (3) Publicly available scientific and medical manuscripts; written media; and web-based reports from pet owners, veterinarians, and other individuals. We identified 231 discreet cyanobacteria harmful algal bloom (cyanoHAB) events and 368 cases of cyanotoxinpoisoning associated with dogs throughout the U.S. between the late 1920s and 2012. The canine cyanotoxin poisoning events reviewed here likely represent a small fraction of cases that occur throughout the U.S. each year.

A case of histamine fish poisoning in a young atopic woman

Histamine fish poisoning, also known as scombroid poisoning, is a histamine toxicity syndrome that results from eating specific types of spoiled fish. Although typically a benign syndrome, characterized by self-limited flushing, headache, and gastrointestinal symptoms, we describe a case unique in its severity and as a precipitant of an asthma exacerbation. A 25-year-old woman presented to the emergency department (ED) with one hour of tongue and face swelling, an erythematous pruritic rash, and dyspnea with wheezing after consuming a tuna sandwich. She developed abdominal pain, diarrhea and hypotension in the ED requiring admission to the hospital. A diagnosis of histamine fish poisoning was made and the patient was treated supportively and discharged within 24 hours, but was readmitted within 3 hours due to an asthma exacerbation. Her course was complicated by recurrent admissions for asthma exacerbations.

[Seafood poisonings. Part II. Fish poisonings]

Fish plays a significant role in human life, mainly as part of a balanced healthy diet and a good source of many of nutrients. However, contact with fish may be harmful or even life-threatening to man. Toxic effects, that fish exerts toward men (ichthyotoxism), result from envenomations by poison. ous fish equipped in venom apparatus (ichthyoacanthotoxism), direct contact with venom produced by skin glandules (ichthyocrinotoxism), or consuming fish containing toxins for nutritional purposes (ichthyosarcotoxism). In the present review, different fish-borne food poisonings are presented including their etiology, pathogenesis, symptomatology and treatment. In fact, the majority of fish poisonings are intoxications with toxins primary produced by bacteria, cyanobacteria and algae. These are consumed and accumulated in the food chain by herbivorous and predatory fish, that in turn may be a cause of poisonings in humans.

Foodborne outbreaks surveillance in the Piedmont Region, Italy (2002-2009)

BACKGROUND

this article summarises the results of eight years (2002-2009) of investigations on food borne disease outbreaks carried out the Regional Agency for Public Health in Piedmont, which is an Italian Region (4,432,571 citizens, 2008).

METHODS

the investigations were conducted as cohort studies supported by laboratory analysis of: food and patients. The data were reported by general practitioners and hospital physicians, and were collected, evaluated and recorded in 22 Hospitals.

RESULTS

it recorded 803 outbreaks of food borne disease, of which 177 mushroom outbreaks with 318 ill people and 499 outbreaks for all the others agents with 3,381 ill people. The maximum prevalence was 15.7/100,000 (2004). The most important causes for numbers of ill people have been (2002-2009): salmonellosis (34%, 1,250/3,699), mushroom poisoning (9%, 318/3,699), Escherichia coli (8%, 228/3,699), Staphyilococcus (6%, 209/3,699), virus (5%, 198/3,699), Clostridium perfringens (4%, 154/3,699), Bacillus cereus (2.1%, 76/3,699), scombrotoxin (1.8%, 65/3,699). 303 out of 304 mushrooms outbreaks occurred from consumers that picking mushrooms themselves to eat in private homes and for all others agents: 57% of 499 the outbreaks occurred in private homes, 27% in restaurants, 6% in canteens, but 39% of 3,381 ill people had eaten in restaurants and other public food facilities, 32% in private homes and 24% in canteens. After mushrooms the eggs (75 outbreaks) were the most important food recognized.

CONCLUSION

the theoretical maximum prevalence which can be hypothesized with this data in Piedmont (2002-2009) is 141/100,000 (sum of the maximum prevalence recorded at least in one Piedmont Hospital district).

Thyroid storm and reversible thyrotoxic cardiomyopathy after ingestion of seafood stew thought to contain marine neurotoxin

BACKGROUND

Thyroid storm and severe decompensated thyrotoxicosis are life-threatening diseases, requiring immediate treatment in an intensive care unit. Thyrotoxic heart disease is common in patients with hyperthyroidism; thyrotoxic cardiomyopathy with poor left ventricular systolic function is rare. Here, we report a patient who presented with severe decompensated thyrotoxicosis and reversible thyrotoxic cardiomyopathy after ingestion of a mixed seafood stew thought to contain tetrodotoxin or a related marine neurotoxin.

SUMMARY

The patient was a 50-year-old woman who was seen at the emergency room of another hospital with altered mentality and flaccid quadriplegia after eating a mixed seafood stew. At the other hospital, she was diagnosed as having tetrodotoxin intoxication on the basis of her clinical presentation. The patient was placed on assisted ventilation and transferred to our hospital the following day because of persisting fever, tachycardia, and respiratory depression. Upon admission, thyroid storm was diagnosed on the basis of thyroid function tests (total triiodothyronine was 354 ng/dL, free thyroxine was 3.45 ng/dL, and thyroid-stimulating hormone was <0.01 mU/L) and clinical manifestations. On the third hospital day, she complained of chest discomfort and progressively worsening dyspnea. Echocardiography showed reduced left ventricular systolic function (left ventricular ejection fraction, 47%; left ventricular fractional shortening, 24.4%) with regional wall motion abnormality of anteroseptal wall and apex and diastolic dysfunction (grade 1, relaxation abnormality), suggesting thyrotoxic cardiomyopathy. She was treated with 10 mCi of radioactive iodine and methimazole, and her thyroid and cardiac function normalized.

CONCLUSION

The patient reported here developed thyroid storm and cardiac decompensation shortly after a clinical event consistent with ingestion of marine neurotoxin. This adds to the list of stresses that have been associated with thyroid storm and emphasizes the need to fully evaluate patients who, on initial evaluation, appear to have only a single disorder.

[The possible causes of the tragedy of "Port Famine" in the Strait of Magellan]

The attempts to colonize the Strait of Magellan soon followed the discovery of this route. PeDro Sarmiento de Gamboa, a Spanish sailor, established human settlements to fortify those lands and control the transit of vessels, especially those of English corsairs, which devastated Chilean and Peruvian coasts. During the summer of 1584, approximately 500 soldiers, artisans, priests, women and children established two villages called "Nombre de Jesús" and "Rey Don Felipe". From the beginning, these settlers had leadership and communication problems and difficulties to obtain food. After three winters only 17 to 18 people survived according to the testimony of one of the survivors, that was rescued by an English sailor named Cavendish, which renamed the village "Rey Don Felipe" as "Port Famine". When he observed the scenes of abandonment and death, he supposed that the settlers died due to lack of food. Other factors that facilitated the desolation were hypothermia, execution, anthropophagy and lesions caused by natives. There is also a possibility that intoxication by red tide (harmful algal bloom) could explain in part the finding of unburied corpses in the strait beaches.

Effects of brevetoxin exposure on the immune system of loggerhead sea turtles

Blooms of the toxic dinoflagellate, Karenia brevis, occur almost annually off the Florida coast. These blooms, commonly called "red tides", produce a group of neurotoxins collectively termed brevetoxins. Many species of sealife, including sea turtles, are severely impacted by brevetoxin exposure. Effects of brevetoxins on immune cells were investigated in rescued loggerhead sea turtles, Caretta caretta, as well as through in vitro experiments using peripheral blood leukocytes (PBL) collected from captive sea turtles. In rescued animals, plasma brevetoxin concentrations were measured using a competitive ELISA. Plasma lysozyme activity was measured using a turbidity assay. Lysozyme activity correlated positively with plasma brevetoxin concentrations. Differential expression of genes affected by brevetoxin exposure was determined using two separate suppression subtractive hybridization experiments. In one experiment, genes from PBL collected from sea turtles rescued from red tide toxin exposure were compared to genes from PBL collected from healthy captive loggerhead sea turtles. In the second experiment, PBL from healthy captive loggerhead sea turtles were exposed to brevetoxin (500 ng PbTx-2/ml) in vitro for 18 h and compared to unexposed PBL. Results from the subtraction hybridization experiment conducted with red tide rescued sea turtle PBL indicated that genes involved in oxidative stress or xenobiotic metabolism were up-regulated. Using quantitative real-time PCR, a greater than 2-fold increase in superoxide dismutase and thioredoxin and greater than 10-fold increase in expression of thiopurine S-methyltransferase were observed. Results from the in vitro subtraction hybridization experiment indicated that genes coding for cytochrome c oxidases were the major up-regulated genes. Using quantitative real-time PCR, a greater than 8-fold increase in expression of beta-tubulin and greater than 3-fold increase in expression of ubiquinol were observed. Brevetoxin exposure may have significant implications for immune function in loggerhead sea turtles.

High-molecular weight protein toxins of marine invertebrates and their elaborate modes of action

High-molecular weight protein toxins significantly contribute to envenomations by certain marine invertebrates, e.g., jellyfish and fire corals. Toxic proteins frequently evolved from enzymes meant to be employed primarily for digestive purposes. The cellular intermediates produced by such enzymatic activity, e.g., reactive oxygen species or lysophospholipids, rapidly and effectively mediate cell death by disrupting cellular integrity. Membrane integrity may also be disrupted by pore-forming toxins that do not exert inherent enzymatic activity. When targeted to specific pharmacologically relevant sites in tissues or cells of the natural enemy or prey, toxic enzymes or pore-forming toxins even may provoke fast and severe systemic reactions. Since toxin-encoding genes constitute "hot spots" of molecular evolution, continuous variation and acquirement of new pharmacological properties are guaranteed. This also makes individual properties and specificities of complex proteinaceous venoms highly diverse and inconstant. In the present chapter we portray high-molecular weight constituents of venoms present in box jellyfish, sea anemones, sea hares, fire corals and the crown-of-thorns starfish. The focus lies on the latest achievements in the attempt to elucidate their molecular modes of action.

[Clinical, epidemiological and treatment aspects of 10 cases of saltwater stingray envenomation]

INTRODUCTION

Stingrays are cartilaginous elasmobranches fishes that can cause severe and potentially fatal injuries in humans.

OBJECTIVE

A descriptive and prospective survey was conducted to analyze epidemiological, clinical and treatment aspects of injuries caused by marine stingrays in Adicora, Paraguaná peninsula, Falcon State, a northwestern, semiarid region of Venezuela.

METHODS

Between December 2006 and April 2007, patients with saltwater stingray injuries, attended in the ambulatory emergency service of Adicora, were clinically examined and interrogated. Treatment consisted on the application of a topical antiseptic solution (povidone-iodine), intravenous administration of an anti-inflammatory analgesic, antibiotic therapy per os and tetanus immunization.

RESULTS

Ten cases of injures caused by the marine stingray Dasyatis guttata (Dasyatidae) were recorded. 6 (60%) of the envenomation cases occurred in males and 4 (40%) in females, being 8 (80%) adults between 20 and 64 years-old and 2 (2%) above that age. Most of the accidents occurred at December and April holidays (90%) and during the late part of the day (80%) when bathing or swimming at or near the beach (70%). The time between ambulatory medical assistance and the accident varied from 5 to 7 minutes, with a mean time of 5.6 +/- 0.84. Injuries were located at lower limbs in all patients with circular lesions of diameters ranging from 1 to 1.53 cm (X: 1.41 +/- 0.22); bleeding was observed in 70% of the cases while 20% showed cellulitis and cutaneous necrosis. Other clinical manifestations were intense local and irradiated pain [Visual analog scale (VAS) = X: 9.5 +/- 0.71)] and erythema (100%). Systemic symptoms included dyspnea (50%) (VAS = X: 5.4 +/- 1.52) and tachycardia (10%). All patients had a satisfactory post-treatment evolution after 20 to 30 minutes (X = 23.1 +/- 3.41) with pain and dyspnea VAS mean values significantly lower (X = 0.55 +/- 0.44; t = 35.5, p = 0.0001; X = 0.1 +/- 0.22; t = 5.57, p = 0.002, respectively). CONCLUSIONS. Injuries caused by the marine stingray D. guttata are a public health problem, appear to have seasonal pattern, and can produce clinical manifestations of significant severity.

Scombroid fish poisoning in Israel, 2005-2007

BACKGROUND

Scombroid fish poisoning is an acute illness caused by consumption of fish containing high concentrations of histamine. Improper handling of fish leads to bacterial contamination. Bacterial enzymes convert histidine to histamine. Symptoms develop quickly and resemble an immunoglobulin E-mediated allergic reaction. The diagnosis is often missed. Serious complications (e.g., bronchospasm, hypotension) are infrequent.

OBJECTIVES

To evaluate the prevalence and characteristics of scombroid fish poisoning in Israel as reported to the national poison information center.

METHODS

We conducted a retrospective poison center chart review from January 2005 to December 2007.

RESULTS

During the study period, 21 events of scombroid poisoning involving 46 patients were recorded. Tuna was the commonest fish consumed (84.7%). Clinical manifestations developed within 20 minutes in 65.2% of the patients. The main clinical manifestations included rash (41%), flushing (37%), gastrointestinal complaints (37%) and headache (30.4%). About 25% had abnormal vital signs; two patients developed hypotension. Treatment was supportive and included mainly H1-antagonists (65.2%) and fluids (13%). Five patients were initially misdiagnosed as having an allergic reaction and were treated with corticosteroids (four patients) and epinephrine (one patient).

CONCLUSIONS

Scombroid fish poisoning should be suspected in patients with histamine-like manifestations that are temporally related to fish (mainly tuna) consumption, especially in outbreaks. Although scombroid poisoning is often self-limited and responds well to antihistamines, prolonged observation may be required as severe toxicity can supervene. Proper handling of fish and urgent notification of the Ministry of Health are mandatory in order to prevent this potentially serious public heath problem.

Hallucinatory Fish Poisoning (Ichthyoallyeinotoxism): Two Case Reports From the Western Mediterranean and Literature Review

Ichthyoallyeinotoxism is a rare kind of food poisoning contracted following the ingestion of fish. The responsible toxins are unknown, and the clinical feature is characterized by the development of CNS disturbances, especially hallucinations and nightmares. As the implicated fish species may be also related to ciguatera poisoning, there may be possible confusion between the two fish-borne intoxications. In order to clarify this, the literature pertaining to "dreamfish" was reviewed and two cases are presented. A 40-year-old man experienced mild digestive troubles and terrifying visual and auditory hallucinations after eating a specimen of Sarpa salpa in a restaurant. As he had severe behaviour troubles, he was managed in the hospital and recovered 36 h after the meal. He was unable to recall the hallucinatory period. Another man, 90-years-old and previously healthy, had auditory hallucinations 2 h after eating a specimen of Sarpa salpa. The two following nights, he had numerous nightmares and recovered spontaneously after a period of 3 days.

Exotic pathology of the hand and foot. A pictorial review

In this article, the imaging findings of the most frequently encountered import pathology of the hand and foot are reviewed, including leprosy, loiasis, snake bites or penetration of spines of sea urchins in the hand and foot. Our objective is to familiarize the radiologist of the Western countries with these diseases, which are still prevalent in developing areas. Due to the rising traveling to foreign countries and continuous immigration, it is important that these disorders be considered in the differential diagnosis in a specific population of asylum-seekers, economic refugees and any other group of persons traveling around the globe. Imaging findings on conventional radiography will be emphasized.

Neurotoxins from marine dinoflagellates: a brief review

Dinoflagellates are not only important marine primary producers and grazers, but also the major causative agents of harmful algal blooms. It has been reported that many dinoflagellate species can produce various natural toxins. These toxins can be extremely toxic and many of them are effective at far lower dosages than conventional chemical agents. Consumption of seafood contaminated by algal toxins results in various seafood poisoning syndromes: paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP), amnesic shellfish poisoning (ASP), diarrheic shellfish poisoning (DSP), ciguatera fish poisoning (CFP) and azaspiracid shellfish poisoning (ASP). Most of these poisonings are caused by neurotoxins which present themselves with highly specific effects on the nervous system of animals, including humans, by interfering with nerve impulse transmission. Neurotoxins are a varied group of compounds, both chemically and pharmacologically. They vary in both chemical structure and mechanism of action, and produce very distinct biological effects, which provides a potential application of these toxins in pharmacology and toxicology. This review summarizes the origin, structure and clinical symptoms of PSP, NSP, CFP, AZP, yessotoxin and palytoxin produced by marine dinoflagellates, as well as their molecular mechanisms of action on voltage-gated ion channels.

Centers for Disease Control and Prevention (CDC). Scombroid fish poisoning associated with tuna steaks--Louisiana and Tennessee, 2006

Scombroid fish poisoning is an acute illness that occurs after eating fish containing high levels of histamine or other biogenic amines. Symptoms typically include facial flushing, sweating, rash, a burning or peppery taste in the mouth, diarrhea, and abdominal cramps and usually resolve within several hours without medical intervention. More severe symptoms (e.g., respiratory distress, swelling of the tongue and throat, and blurred vision) can occur and require medical treatment with antihistamines. In late 2006, two outbreaks of scombroid fish poisoning occurred, one in Louisiana and one in Tennessee. To determine the source of the outbreaks and to implement control measures, CDC and the state health departments in Louisiana and Tennessee conducted epidemiologic investigations, and the Food and Drug Administration (FDA) conducted traceback investigations of the product. This report describes the results of those investigations, which indicated that the outbreaks in Louisiana and Tennessee were associated with tuna steaks from Indonesia and Vietnam, respectively. The majority of seafood eaten in the United States is imported. FDA programs to identify and prevent seafood hazards such as scombroid fish poisoning have made substantial progress but are able to inspect only a small proportion of seafood entering the United States. The only effective method for prevention of scombroid fish poisoning is consistent temperature control of fish at </=40 degrees F (</=4.4 degrees C) at all times between catching and consumption.

First report of homoanatoxin-a and associated dog neurotoxicosis in New Zealand

In November 2005, at least five dogs died rapidly after contact with water from the Hutt River (lower North Island, New Zealand). Necropsy performed 24h later on one of the dogs (a 20-month-old Labrador) revealed few findings of interest, except for copious amounts of froth in the respiratory tract down to the bifurcation of the trachea and large quantities of algal material in the dog's stomach. Low and relatively stable flows in the Hutt River during spring had resulted in the proliferation of benthic cyanobacteria that formed large black/brown mats along the river edge. Samples from the Labrador's stomach contents and cyanobacterial mats were analysed microscopically and screened using chemical and biochemical assays for cyanotoxins: anatoxin-a, homoanatoxin-a, cylindrospermopsins, saxitoxins and microcystins. Liquid chromatography-mass spectrometry (LC-MS) confirmed the presence of the neurotoxic cyanotoxins anatoxin-a and homoanatoxin-a and their degradation products, dihydro-anatoxin-a and dihydro-homoanatoxin-a. This is the first report of homoanatoxin-a and associated degradation product in New Zealand. Based on morphology, the causative species was identified as Phormidium sp. Subsequent phylogenetic analysis of 16S rRNA gene sequences demonstrated that the causative organism was most similar to Phormidium autumnale. Further investigations led to the detection of homoanatoxin-a and anatoxin-a in cyanobacterial mats from four other rivers in the Wellington region (lower North Island, New Zealand). Access restrictions were placed on over 60% of river catchments in the western Wellington region, severely affecting recreational users.

TRPV1 as a key determinant in ciguatera and neurotoxic shellfish poisoning

Ciguatera fish poisoning and neurotoxic shellfish poisoning are distinct clinical entities characterized by gastrointestinal and neurological disturbances, following the consumption of certain reef fish and shellfish containing toxic polyether compounds sporadically present in certain toxic marine dinoflagellates. The biotransformation and bioaccumulation of gambierol and brevetoxin, and their congeners, are believed to be involved in the pathogenesis of these "food-chain diseases", for which no effective treatments are available. Here, we describe for the first time the potent effect of gambierol and brevetoxin on TRPV1 channels, a key player in thermal and pain sensation. Our findings may lead to promising new therapeutic interventions.

Chelonitoxism: New case reports in French Polynesia and review of the literature

Eating the flesh of some marine turtles can cause a type of seafood poisoning called chelonitoxism. The purpose of this article is to report a new case of mass poisoning caused by consumption of sea turtle flesh in French Polynesia. The episode involved 19 members of the same family. Three persons required hospitalization after consuming two consecutive meals including turtle flesh. One 26-year-old woman who was pregnant at 14 weeks of amenorrhea lapsed into a coma and died due to multiorgan failure on the third day after the meal. This case confirms the potential severity of chelonitoxism as reported in several series in the literature showing high mortality rates. The causative toxins are currently unidentified. Further study is needed to better understand chelonitoxism.

Food Poisoning

Food poisoning is encountered throughout the world. Many of the toxins responsible for specific food poisoning syndromes are no longer limited to isolated geographic locations. With increased travel and the ease of transporting food products, it is likely that a patient may present to any emergency department with the clinical effects of food poisoning. Recognizing specific food poisoning syndromes allows emergency health care providers not only to initiate appropriate treatment rapidly but also to notify health departments early and thereby prevent further poisoning cases. This article reviews several potential food-borne poisons and describes each agent's mechanism of toxicity, expected clinical presentation, and currently accepted treatment.

Influence of the sample toxic profile on the suitability of a high performance liquid chromatography method for official paralytic shellfish toxins control

An HPLC-FLD method, involving pre-chromatographic oxidation of the PSP toxins with hydrogen peroxide and periodate, has been AOAC validated through a collaborative trial and adopted as AOAC Official Method. This method could be a candidate for replacing the mouse bioassay (MBA) for the Official Control of PSP toxins at European level, once accepted by the legislation. An interlaboratory exercise has been organized by the CRLMB to evaluate its "fitness for purpose" for the Official Control of PSP toxins in the EU laboratories. Eighteen EU laboratories took part in the study and had to analyze six bivalve mollusc samples with several PSP toxic profiles. The performance of the participant laboratories in the application of this method was compared with that obtained at the collaborative trial. Information on problems/drawbacks encountered by participants in the application of this method was also sought. The HPLC validated method is only applicable for Official PSP Control for certain samples. This depends on sample PSP toxic profile. Results obtained for samples where only GTX2,3 and STX were present were satisfactory and in agreement with MBA results. Results obtained for a sample with a toxic profile dominated by GTX6 and suspected to contain also C1,2 and C3,4 were not satisfactory. GTX5 and dc-STX could be quantified, although the results achieved (total toxicity) were lower than those obtained by MBA. It can be also useful as a screening method, complementary to MBA, helping in the reduction of the animals used. However, the lack of several PSP standards, the fact that the method is not validated for all the PSP toxins, and several drawbacks found in its application are a handicap to fully implement it for Official PSP Control as a viable replacement for bioassay.

Case of the month: Lesson of the week: don't forget scombroid

We describe five cases of scombroid that presented as one incident. We discuss the aetiology, clinical features, differential diagnosis and treatment of this condition.

Is hot water immersion an effective treatment for marine envenomation?

Envenomation by marine creatures is common. As more people dive and snorkel for leisure, the incidence of envenomation injuries presenting to emergency departments has increased. Although most serious envenomations occur in the temperate or tropical waters of the Indo-Pacific region, North American and European waters also provide a habitat for many stinging creatures. Marine envenomations can be classified as either surface stings or puncture wounds. Antivenom is available for a limited number of specific marine creatures. Various other treatments such as vinegar, fig juice, boiled cactus, heated stones, hot urine, hot water, and ice have been proposed, although many have little scientific basis. The use of heat therapies, previously reserved for penetrating fish spine injuries, has been suggested as treatment for an increasing variety of marine envenomation. This paper reviews the evidence for the effectiveness of hot water immersion (HWI) and other heat therapies in the management of patients presenting with pain due to marine envenomation.

A fishy cause of sudden near fatal hypotension

Seafood-borne illnesses are a common but under recognised source of morbidity. We report the case of an 80-year-old woman who presented to hospital after collapsing in a restaurant following lunch consisting of mackerel fish. A detailed food history and clinical exclusion helped diagnose the condition as scombroid poisoning. The patient made a complete recovery following antihistamine therapy.

Saxitoxin puffer fish poisoning in the United States, with the first report of Pyrodinium bahamense as the putative toxin source

BACKGROUND

From January 2002 to May 2004, 28 puffer fish poisoning (PFP) cases in Florida, New Jersey, Virginia, and New York were linked to the Indian River Lagoon (IRL) in Florida. Saxitoxins (STXs) of unknown source were first identified in fillet remnants from a New Jersey PFP case in 2002.

METHODS

We used the standard mouse bioassay (MBA), receptor binding assay (RBA), mouse neuroblastoma cytotoxicity assay (MNCA), Ridascreen ELISA, MIST Alert assay, HPLC, and liquid chromatography-mass spectrometry (LC-MS) to determine the presence of STX, decarbamoyl STX (dc-STX), and N-sulfocarbamoyl (B1) toxin in puffer fish tissues, clonal cultures, and natural bloom samples of Pyrodinium bahamense from the IRL.

RESULTS

We found STXs in 516 IRL southern (Sphoeroides nephelus), checkered (Sphoeroides testudineus), and bandtail (Sphoeroides spengleri) puffer fish. During 36 months of monitoring, we detected STXs in skin, muscle, and viscera, with concentrations up to 22,104 microg STX equivalents (eq)/100 g tissue (action level, 80 microg STX eq/100 g tissue) in ovaries. Puffer fish tissues, clonal cultures, and natural bloom samples of P. bahamense from the IRL tested toxic in the MBA, RBA, MNCA, Ridascreen ELISA, and MIST Alert assay and positive for STX, dc-STX, and B1 toxin by HPLC and LC-MS. Skin mucus of IRL southern puffer fish captive for 1-year was highly toxic compared to Florida Gulf coast puffer fish. Therefore, we confirm puffer fish to be a hazardous reservoir of STXs in Florida's marine waters and implicate the dinoflagellate P. bahamense as the putative toxin source.

CONCLUSIONS

Associated with fatal paralytic shellfish poisoning (PSP) in the Pacific but not known to be toxic in the western Atlantic, P. bahamense is an emerging public health threat. We propose characterizing this food poisoning syndrome as saxitoxin puffer fish poisoning (SPFP) to distinguish it from PFP, which is traditionally associated with tetrodotoxin, and from PSP caused by STXs in shellfish.

Evaluation of methods for the isolation, detection and quantification of cyanobacterial hepatotoxins

Cyanobacterial hepatotoxins such as microcystins and nodularins have been responsible for the poisoning of both animals and humans who ingest or come into contact with toxic blooms. They are extremely stable in water due to their stable chemical structure and can tolerate radical changes in water chemistry, including pH and salinity. Different methods for the extraction and detection of these compounds have been reported. Extraction methods utilizing both aqueous and organic solvent systems have been reported. The detection methods ranging from immunological or biochemical assays such as enzyme linked immunosorbent assays (ELISA) and enzyme activity assays, to chemicals methods such as high performance liquid chromatography (HPLC) and more sophisticated liquid chromatography-mass spectrometry (LC-MS) have been documented as well. We review some important aspects of cyanobacterial hepatotoxins and methods of analysis for these toxins.