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PubMed2005

Year-round screening of noncommercial and commercial oysters for the presence of human pathogenic viruses.

Consumption of virus-contaminated shellfish has caused numerous outbreaks of gastroenteritis and hepatitis worldwide. In The Netherlands, oysters are cultured and imported both for consumption and export; therefore, the presence of noroviruses, rotaviruses, astroviruses, hepatitis A viruses, and enteroviruses was determined in 64 commercial and noncommercial oyster samples. Oysters were collected monthly for 13 months from four different harvesting areas in the Oosterschelde Delta. Oyster samples were classified by determining Escherichia coli levels according to the standards set by the Councils Directive (91/ 492/EEC). Two of 36 commercial and 2 of 28 noncommercial oyster samples were B-classified and therefore not ready for consumption. All other oyster samples were A-classified. For the detection of viral RNA, 150 mg of hepatopancreatic tissue was subjected to the Qiagen RNeasy Mini Kit, followed by reverse transcriptase (RT)-PCR and Southern blot hybridization. Enterovirus RNA was detected in 14 of 64 oyster samples, of which 4 were from noncommercial oyster harvesting areas and 10 were from commercial harvesting areas. None of the other human pathogenic viruses were detected. The levels of somatic coliphages and F-specific phages were also determined in all 64 oyster samples, with some samples containing high phage levels (>50 PFU/g of hepatopancreatic tissue), but with most samples containing low phage levels (<50 PFU/g of hepatopancreatic tissue). However, independent of these high or low phage levels, enterovirus RNA could be detected. Thus, commercial oysters can be contaminated with pathogenic viruses, and monitoring only fecal indicators might not sufficiently protect human health.

Animals↗

PubMed2006

Cryptosporidium contamination in harvesting areas of bivalve molluscs.

Cryptosporidium contamination was evaluated in areas in Galicia (northwestern Spain) where bivalve molluscs are harvested. Galicia is the main mussel-producing region in Europe. Data were collected on water contamination of effluents that are discharged into these areas. Cryptosporidium spp. were detected by immunofluorescence microscopy and molecular methods in 71% of the river water samples (n = 7), 64% of raw sewage samples (n = 11), 50% of effluents from wastewater treatment plants (n = 16), and 29.3% of the mussel samples (Mytilus galloprovincialis, n = 184). Cryptosporidium parvum was identified in all samples of contaminated mussels, Cryptosporidium muris was found in three samples of effluent from wastewater treatment plants, and Cryptosporidium baileyi was found in a sample of raw sewage. Further studies are needed to determine the parasitological quality of water in these shellfish harvesting and recreational areas. Cryptosporidium could be a public health risk from consumption of raw or undercooked contaminated molluscs and use of contaminated waters for recreational purposes.

Animals↗

PubMed2006

Effect of heat treatment on hepatitis A virus and norovirus in New Zealand greenshell mussels (Perna canaliculus) by quantitative real-time reverse transcription PCR and cell culture.

Quantitative real-time reverse transcription PCR (qRT-PCR) and cell culture (50% tissue culture infectious dose [TCID50]) were used to determine the effect of heat treatments on norovirus and hepatitis A virus (HAV) in the New Zealand Greenshell mussel (Perna canaliculus). Since it is common practice to cook mussels until the shells open, internal temperatures and opening times of mussels on boiling and steaming were determined at regular time intervals. Fifty mussels in batches of six were exposed to boiling and steaming. A mean internal temperature of 90 degrees C (recommended for virus inactivation when maintained for 90 s) was reached after boiling for 170 s, with all 50 mussels open at 210 s. For steaming, the mean internal temperature achieved was only 83 degrees C after 300 s, and all 50 mussels were open. When mussels were steamed for 180 s (mean internal temperature of 63 degrees C), a significant 1.5-log decrease in the HAV titer (log TCID50) was observed. Following the immersion of mussels in boiling water for 180 s (mean internal temperature of 92 degrees C), no viable HAV was detected. For both boiling and steaming experiments, there was no significant change in the norovirus or HAV qRT-PCR titers compared with the controls. Our results show that when New Zealand Greenshell mussels open on heating, their internal temperature may not reach the parameters required for virus inactivation. Immersion for a minimum of 3 min in boiling water rather than steaming is recommended to reduce the risk of viral foodborne illness from contaminated shellfish.

Bivalvia↗

PubMed1999

A review of selected seafood poisonings.

Seafood poisoning has been recognized as a problem in both coastal and inland populations for millennia. Many types of sea creatures from shellfish to the largest fish have been implicated. Severe cases of many different types of seafood poisonings can result in fatalities. While the pathophysiology of the toxins is well known in some cases, others, like ciguatera, remain somewhat confusing. As a result, the treatment of these conditions remains controversial, although supportive care continues to be the mainstay of therapy. In this manuscript, we review the pathophysiology, clinical presentation, and treatment of some of the most common and toxic varieties of seafood poisoning resulting from toxins.

Animals↗

PubMed1976

Vibrio parahaemolyticus-food poisoning: case report.

Symptoms of food poisoning occurred following the ingestion of raw shellfish purchased in the Auckland area. Vibrio parahaemolyticus was recoverer from the patient. The potential of this and closely related microorganisms to cause illness is reviewed.

Adult↗

PubMedDate not supplied

Rapid food decomposition by H2O2-H2SO4 for determination of total mercury by flow injection cold vapor atomic absorption spectrometry.

A mixture of 50% H2O2-H2SO4 (3 + 1, v/v) was used for decomposition of food in open vessels at 80 degrees C. The treatment allowed rapid total mercury determination by flow injection cold vapor atomic absorption spectrometry. Cabbage, potatoes, peanuts paste, hazelnuts paste, oats, tomatoes and their derivatives, oysters, shrimps, prawns, shellfish, marine algae, and many kinds of fish were analyzed by the proposed methodology with a limit of quantitation of 0.86 +/- 0.08 microg/L mercury in the final solution. Reference materials tested also gave excellent recovery.

Animals↗

PubMedDate not supplied

Characterization of microbial communities from coastal waters using microarrays.

Molecular methods, including DNA probes, were used to identify and enumerate pathogenic Vibrio species in the Chesapeake Bay; our data indicated that Vibrio vulnificus exhibits seasonal fluctuations in number. Our work included a characterization of total microbial communities from the Bay; development of microarrays that identify and quantify the diversity of those communities; and observation of temporal changes in those communities. To identify members of the microbial community, we amplified the 16S rDNA gene from community DNA isolated from a biofilm sample collected from the Chesapeake Bay in February, 2000. The resultant 75 sequences were 95% or more similar to 7 species including two recently described Shewanella species, baltica and frigidimarina, that have not been previously isolated from the Chesapeake. When the genera of bacteria from biofilm after culturing are compared to those detected by subcloning amplified 16S fragments from community DNA, the cultured sample exhibited a strong bias. In oysters collected in February, the most common bacteria were previously unknown. Based on our 16S findings, we are developing microarrays to detect these and other microbial species in these estuarine communities. The microarrays will detect each species using four distinct loci, with the multiple loci serving as an internal control. The accuracy of the microarray will be measured using sentinel species such as Aeromonas species, Escherichia coli, and Vibrio vulnificus. Using microarrays, it should be possible to determine the annual fluctuations of bacterial species (culturable and non-culturable, pathogenic and non-pathogenic). The data may be applied to understanding patterns of environmental change; assessing the "health" of the Bay; and evaluating the risk of human illness associated with exposure to and ingestion of water and shellfish.

Animals↗

PubMed2003

Factors influencing faecal contamination in coastal marinas.

Recreational pleasure and fishing boats are potential sources of human faecal contamination because the sanitary wastes from boat occupants may be discharged into the surrounding water. The impacts of such faecal contamination from boats is potentially high in marinas where boats are often kept and occupied for varying periods of time. The nature and extent of such faecal contamination from boats in marinas of different design and use is still inadequately understood. In this study the levels of faecal coliform (FC) bacteria were measured in the waters of a confined and an open water marina over a 6 d period encompassing a holiday weekend. Levels of FC rose with increasing occupancy by boats and boaters during the study period and then declined again. FC levels were higher in waters of a confined or basin marina than in waters of an open or unconfined marina. In both confined and open water marinas, FC levels were highest in water samples collected near boats but they also became elevated on occasion in water samples taken a distance of 305 m from boats. Concentrations of FC in marina waters exceeded the standards and guidelines for shell-fishing and primary contact recreation waters. Therefore, greater consideration of human health risks from enteric microbes in marina waters and shellfish is recommended.

Animals↗

PubMed2003

[Microbiological risk associated with seafood consumption].

Seafood has always been an important source for human nutrition. The increase of its consumption, however, and the epidemiological data, confirming the role of seafood, especially shellfish, as a carrier of foodborne toxinfections, has brought the need of a greater control of his microbiological characteristics. In this review we considered the main pathogenous microorganisms associated to such products, with a special attention towards the emerging pathogens not yet considered in the legislation (autochthonous pathogens, e.g. vibrios and enteric viruses). We examined the conditions of their presence and survival in the marine environment, the mechanisms through which they contaminate seafood and their resistance to the treatments endured by food before the commercialization and at the moment of the consumption.

Animals↗

PubMed2003

[Effects of marine bacteria on the growth and toxin production of red-tide algae under different pH and salinities].

The effects of strain S10 isolated from sediments of Xiamen Western Sea Area on the growth and paralytic shellfish poison (PSP) production of Alexandrium tamarense at different pH and salinities were studied. The results showed that the alga grew well at pH 6-8 and at salinity of 20-34. The toxicity of A. tamarense varied markedly at different pH and salinities: it decreased with increasing pH, while increased with salinity and reached its peak value at the salinity of 30, and then declined. The strain S10 inhibited the growth and the PSP production of A. tamarense at different pH and salinities. It had the best inhibitory function on the growth of A. tamarense at pH 7 and salinity of 34. The best inhibitory function on the PSP production of A. tamarense was at pH 7, but this inhibitory function was not related to salinity.

Bacteria↗

PubMedDate not supplied

[Food-borne human pathogenic viruses and their molecular detection with special consideration of noroviruses and hepatitis A virus in mussels].

Viruses are increasingly important as etiological agents of gastrointestinal infections. Because of improved diagnostic methods, in particular, because of molecular biological techniques, viruses can be detected much more frequently as pathogens of foodborne diseases. Apart from the hepatitis A virus (HAV) the Norovirus (NLV) is becoming more significant. On an international level methods are developed to detect the amount of viruses which minimise PCR inhibitors and which are applicable in routine diagnostic. There are numerous routines available in the field of virus diagnostic in shellfish and oysters which are, however, not yet standardised and applicable in the whole of Europe. This review highlights viral agents their characteristics as well as food contaminated with viruses. While most of the detection methods are cited from the literature, own preliminary results of virus detection in mussels are discussed in addition.

Animals↗

PubMed2004

Severe food anaphylaxis: 107 cases registered in 2002 by the Allergy Vigilance Network.

BACKGROUND: The prevalence of food allergies increases, relating to diet modifications. The consumption of new foods--exotic foods or foods originally used for animal feed, new proteins, neo allergens due to the use of new technologies and soon, Genetically Modified Foods--are in the spotlight. OBJECTIVE: It is essential to develop a system of food allergy vigilance encompassing the full range of foods being consumed. Understanding this imperative leads logically to the suggestion of developing an allergy vigilance network taking advantage of the ongoing experience of allergists "on the ground". METHODS: The French Allergy Vigilance Network is subscribed to by 302 allergologists (267 of whom are French). The aims of the Network are to record cases of severe anaphylaxis, to establish an epidemiological data bank from prospective multicenter studies, and to monitor the allergic risk from novel foods. RESULTS: In 2002, 107 cases of severe anaphylaxis were recorded: anaphylactic shock--59.8% (one fatal), systemic reaction--18.7%, laryngeal angio-edema--15.9%, acute severe asthma--5.6% (one fatal). The main allergens identified were peanuts, nuts, shellfish, lupine flour and wheat flour. Action has been taken as a result: information by industry on inadequate labeling, withdrawal of wrongly labeled batches, and university hospital centers have been encouraged to establish the allergenic safety of their catering services. CONCLUSION: Setting up such a network in other countries would lead to a significant advance in knowledge of the peculiarities of allergies relating to a wide variety of eating habits.

Adult↗

PubMedDate not supplied

Quantitative analysis of iron-containing protein myoglobin in different foodstuffs by liquid chromatography coupled to high-resolution inductively coupled plasma mass spectrometry.

Quantitative determination was made of the iron-containing protein myoglobin in a range of different foods, including meat, processed meat, fish, and shellfish, by liquid chromatography coupled to a double-focusing sector field inductively coupled plasma mass spectrometry (ICP-MS). The concentration of myoglobin determined in the samples ranged from 0 to 6.5 mg/kg, and the analytical precision (coefficient of variation) for the analysis of 8 replicate raw steak extracts was 2.1%. By using a double-focusing ICP-MS instrument, direct on-line detection of the most abundant iron isotope 56Fe was possible without interference from a major polyatomic interference (40Ar16O). Separation of myoglobin from other iron-containing compounds was facilitated by use of a gel filtration column (TSK Gel G2000SW) and Tris buffer (pH 7.2). The chromatographic column was coupled directly to the nebulizer of the ICP-MS instrument by a short piece of PEEK tubing. To ensure sufficient quality control throughout the study, a raw beefsteak sample was developed as an in-house reference material. The concentration of the heme-iron-containing protein myoglobin in this sample was determined by the developed method and independently by a conventional spectrophotometric method. The agreement between the 2 analytical techniques was very good. The detection limit (3 times the signal/noise ratio for a blank) of the reported method for myoglobin was 0.85 ng Fe/L.

Animals↗

PubMedDate not supplied

[Detection of Salmonella, Listeria spp., Vibrio spp., and Yersinia enterocolitica in frozen seafood and comparison with enumeration for faecal indicators: implication for public health].

Infections transmitted through consumption of contaminated seafood is a significant source of human morbidity. The aim of this study was to compare the detection of Salmonella, Listeria, Vibrio, and Yersinia enterocolitica in frozen seafood with results from enumeration of conventional faecal indicators. A total of 213 crustaceans or molluscs were purchased from local vendors in Italy: 74% were harvested in Italy, 25% from other European countries and 1% from outside Europe. Listeria spp. was isolated from 20% of samples, Vibrio spp. from 11%, Salmonella from 3% and Y. enterocolitica from 1%. Listeria species isolated were L. monocytogenes, L. innocua, L. welshimeri, L. ivanovii and L. seeligeri. Vibrio species isolated were V. alginolyticus and V. fluvialis. The most contaminated shellfish for both faecal indicator microrganism and pathogens were hen clams (6% contained Salmonella, 27% Listeria spp. and 3% Y. enterocolitica), while from 27% of shrimps Vibrio spp. was recovered. Higher levels of faecal indicators were recovered from samples harvested outside Europe, and 66% of samples harvested in Thailand were contaminated from Salmonella. Significant differences were found in the levels of contamination of seafoods depending upon the freezing regime, but there was a limited association between presence of potential pathogens (particularly Vibrio spp.) and conventional faecal indicators. Hence, we suggest reconsideration of current legal parameters to evaluate microbiological quality of seafood.

Feces↗

PubMed2003

Estimating the global burden of thalassogenic diseases: human infectious diseases caused by wastewater pollution of the marine environment.

This paper presents a preliminary attempt at obtaining an order-of-magnitude estimate of the global burden of disease (GBD) of human infectious diseases associated with swimming/bathing in coastal waters polluted by wastewater, and eating raw or lightly steamed filter-feeding shellfish harvested from such waters. Such diseases will be termed thalassogenic--caused by the sea. Until recently these human health effects have been viewed primarily as local phenomena, not generally included in the world agenda of marine scientists dealing with global marine pollution problems. The massive global scale of the problem can be visualized when one considers that the wastewater and human body wastes of a significant portion of the world's population who reside along the coastline or in the vicinity of the sea are discharged daily, directly or indirectly, into the marine coastal waters, much of it with little or no treatment. Every cubic metre of raw domestic wastewater discharged into the sea can carry millions of infectious doses of pathogenic microorganisms. It is estimated that globally, foreign and local tourists together spend some 2 billion man-days annually at coastal recreational resorts and many are often exposed there to coastal waters polluted by wastewater. Annually some 800 million meals of potentially contaminated filter-feeding shellfish/bivalves and other sea foods, harvested in polluted waters are consumed, much of it raw or lightly steamed. A number of scientific studies have shown that swimmers swallow significant amounts of polluted seawater and can become ill with gastrointestinal and respiratory diseases from the pathogens they ingest. Based on risk assessments from the World Health Organization (WHO) and academic research sources the present study has made an estimate that globally, each year, there are in excess of 120 million cases of gastrointestinal disease and in excess of 50 million cases of more severe respiratory diseases caused by swimming and bathing in wastewater-polluted coastal waters. Filter-feeding shellfish/bivalves, which are often harvested from wastewater-polluted areas of the sea, can effectively filter out and concentrate the microbial pathogens in the seawater. It can be roughly estimated that annually there are some 4 million cases of infectious hepatitis A and E (HAV/HEV), with some 40 thousand deaths and 40 thousand cases of long-term disability, mainly chronic liver damage, from consuming raw or lightly steamed filter-feeding shellfish/molluscs harvested globally from polluted coastal waters. The total global health impact of the thalassogenic diseases--human infectious diseases associated with pathogenic microorganisms from land-based wastewater pollution of the seas--is estimated to be about 3 million 'disability-adjusted life years' (DALY)/year, with an estimated economic loss of some 12 billion dollars per year. Due to the preliminary nature of the estimates in this study it is appropriate to assume that all of the above figures are no more than first approximations and that the true figures may be 50% higher or lower. Nevertheless, it is the author's belief that this study indicates that wastewater pollution of the sea results in a multi-billion dollar per year health burden and that preventing wastewater pollution of the sea is worthy of inclusion on the global agenda of marine pollution prevention and control.

Bacterial Infections↗

PubMedDate not supplied

[Enteric viruses and bacteriological parameters in molluscs].

Eighty-seven samples of shellfish were collected considering: type of mollusc, origin, growing area, monitoring or for human purpose. The bacteriological parameters were: Fecal Coliforms, Escherichia coli, and Salmonella; whereas the virological parameters included: Hepatitis A and E virus, Rotavirus, Astrovirus and Enterovirus. In total, 63.2% of samples had normal bacteria values, only one sample was Salmonella positive. The percentage of positive samples for Hepatitis A virus was 5.7%, Rotavirus 29.9%, Astrovirus 27.6%, Enterovirus 10.3%. The recovery of hepatitis E virus was always negative, whereas 13 samples (14.9%) were positive for two viruses.

Animals↗

PubMed2004

[Successful treatment of allergic purpura nephritis associated with thrombotic microangiopathy using plasma exchange: a case report].

A 73-year-old man, who had an allergy to shellfish, was admitted to our hospital because of proteinuria, hematuria, purpura and extremity edema after eating oysters. Laboratory data on admission were proteinuria 2.0 g/day, hematuria 3+, serum creatinine (Cr) 1.2 mg/dl, total protein 6.3 g/dl, and albumin 3.1 g/dl. He presented a high fever with neutrophilia and rapid deterioration of renal function after admission. Based on the skin biopsy, we made a diagnosis of leukocytoclastic vasculitis with IgA deposition. Oral prednisolone (40 mg/day) following drip intravenous methylprednisolone (500 mg/day, 3 days) was administered. However, renal function and urinary findings showed no sign of improvement. In the first renal biopsy, although there were no crescentic formations, most of the glomeruli showed thrombotic microangiopathy and endocapillary proliferation with IgA deposition and electron dense deposits. Therefore, a plasma exchange was performed resulting in an improvement of the renal function. The serum Cr. level was reduced from 2.7 to 0.8 mg/dl and proteinuria from 3.7 to 0.1 g/day. In the second biopsy, the electron dense deposits with an IgA deposition had disappeared. These findings suggested that plasma exchange was effective in leading remission in a case of allergic purpura nephritis associated with thrombotic microangiopathy.

Aged↗

PubMed2005

Future increase in harmful algal blooms in the North Sea due to climate change.

In temperate seas such as the North Sea harmful (toxic) algal blooms will probably increase as a result of climate change. This conclusion was reached after investigating the projected effect of climate change for the year 2100 in Dutch coastal waters (4 degrees C temperature rise and increased water column stratification) on the growth rates of six harmful and two non-harmful phytoplankton species. Micro algae form the basis of the marine food chain. However, toxin-producing species may seriously disrupt the food web and lead to fish kills and human intoxication. Two species with estimated doubled growth rates in 2100, F. japonica and C. antiqua, entered Europe via ship's ballast water or shellfish imports. This stresses the need to legally regulate such invasion routes in order to prevent the import of novel species. Future toxic phytoplankton blooms may further devaluate ecosystem deliverables such as fish production or recreational use. This devaluation can be estimated by monetary value assessments that are needed in cost-benefit analyses for policy guidance. The lack of understanding of future climate, ecosystem functioning and its response to climate change calls for a scientific effort to improve our knowledge on present day coastal ecosystem functioning and its resilience.

Animals↗