Biomedical subjects

L Lehane

Publications and source records attributed to L Lehane.

7 recordsLinked to original sources

PubMed2001

Paralytic shellfish poisoning: a potential public health problem.

Paralytic shellfish poisoning (PSP) is a serious illness in which neurological symptoms predominate. Recovery is usually complete and uncomplicated, but in severe cases there may be respiratory paralysis and death. Most cases follow consumption of bivalve molluscs that have filter-fed on toxic marine microalgae (phytoplankton). Microalgae capable of causing the intoxication have been recorded in all States of Australia, and major toxic blooms have occurred in Tasmania, Victoria and South Australia.

Adult↗

PubMed2000

Ciguatera: recent advances but the risk remains.

Ciguatera is an important form of human poisoning caused by the consumption of seafood. The disease is characterised by gastrointestinal, neurological and cardiovascular disturbances. In cases of severe toxicity, paralysis, coma and death may occur. There is no immunity, and the toxins are cumulative. Symptoms may persist for months or years, or recur periodically. The epidemiology of ciguatera is complex and of central importance to the management and future use of marine resources. Ciguatera is an important medical entity in tropical and subtropical Pacific and Indian Ocean regions, and in the tropical Caribbean. As reef fish are increasingly exported to other areas, it has become a world health problem. The disease is under-reported and often misdiagnosed. Lipid-soluble, polyether toxins known as ciguatoxins accumulated in the muscles of certain subtropical and tropical marine finfish cause ciguatera. Ciguatoxins arise from biotransformation in the fish of less polar ciguatoxins (gambiertoxins) produced by Gambierdiscus toxicus, a marine dinoflagellate that lives on macroalgae, usually attached to dead coral. The toxins and their metabolites are concentrated in the food chain when carnivorous fish prey on smaller herbivorous fish. Humans are exposed at the end of the food chain. More than 400 species of fish can be vectors of ciguatoxins, but generally only a relatively small number of species are regularly incriminated in ciguatera. Ciguateric fish look, taste and smell normal, and detection of toxins in fish remains a problem. More than 20 precursor gambiertoxins and ciguatoxins have been identified in G. toxicus and in herbivorous and carnivorous fish. The toxins become more polar as they undergo oxidative metabolism and pass up the food chain. The main Pacific ciguatoxin (P-CTX-1) causes ciguatera at levels=0.1 microg/kg in the flesh of carnivorous fish. The main Caribbean ciguatoxin (C-CTX-1) is less polar and 10-fold less toxic than P-CTX-1. Ciguatoxins activate sodium ion (Na ) channels, causing cell membrane excitability and instability. Worldwide coral bleaching is now well documented, and there is a strong association between global warming and the bleaching and death of coral. This, together with natural environmental factors such as earthquakes and hurricanes, and man-made factors such as tourism, dock construction, sewage and eutrophication, may create more favourable environments for G. toxicus. While low levels of G. toxicus are found throughout tropical and subtropical waters, the presence of bloom numbers is unpredictable and patchy. Only certain genetic strains produce ciguatoxins, and environmental triggers for increasing toxin production are unknown.

Acute Disease↗

PubMed2000

Update on histamine fish poisoning.

Histamine fish poisoning (HFP) is a chemical intoxication that occurs after eating bacterially contaminated fish of particular species. Its incidence has been underestimated because of its frequently mild nature, lack of mandatory reporting, and misdiagnosis (most often as seafood allergy). The fish are non-toxic when caught, but increase in histamine content as bacterial numbers increase. They may look and smell normal, and cooking does not destroy the histamine. Although the condition is caused by histamine intoxication, its pathogenesis is not fully understood, and other toxins or potentiators may be involved.

Animals↗

PubMed2000

Histamine fish poisoning revisited.

Histamine (or scombroid) fish poisoning (HFP) is reviewed in a risk-assessment framework in an attempt to arrive at an informed characterisation of risk. Histamine is the main toxin involved in HFP, but the disease is not uncomplicated histamine poisoning. Although it is generally associated with high levels of histamine (> or =50 mg/100 g) in bacterially contaminated fish of particular species, the pathogenesis of HFP has not been clearly elucidated. Various hypotheses have been put forward to explain why histamine consumed in spoiled fish is more toxic than pure histamine taken orally, but none has proved totally satisfactory. Urocanic acid, like histamine, an imidazole compound derived from histidine in spoiling fish, may be the "missing factor" in HFP. cis-Urocanic acid has recently been recognised as a mast cell degranulator, and endogenous histamine from mast cell degranulation may augment the exogenous histamine consumed in spoiled fish. HFP is a mild disease, but is important in relation to food safety and international trade. Consumers are becoming more demanding, and litigation following food poisoning incidents is becoming more common. Producers, distributors and restaurants are increasingly held liable for the quality of the products they handle and sell. Many countries have set guidelines for maximum permitted levels of histamine in fish. However, histamine concentrations within a spoiled fish are extremely variable, as is the threshold toxic dose. Until the identity, levels and potency of possible potentiators and/or mast-cell-degranulating factors are elucidated, it is difficult to establish regulatory limits for histamine in foods on the basis of potential health hazard. Histidine decarboxylating bacteria produce histamine from free histidine in spoiling fish. Although some are present in the normal microbial flora of live fish, most seem to be derived from post-catching contamination on board fishing vessels, at the processing plant or in the distribution system, or in restaurants or homes. The key to keeping bacterial numbers and histamine levels low is the rapid cooling of fish after catching and the maintenance of adequate refrigeration during handling and storage. Despite the huge expansion in trade in recent years, great progress has been made in ensuring the quality and safety of fish products. This is largely the result of the introduction of international standards of food hygiene and the application of risk analysis and hazard analysis and critical control point (HACCP) principles.

Disease Outbreaks↗

PubMed2000

Ciguatera update.

Ciguatera fish poisoning is probably more important than any other form of seafood poisoning. Its epidemiology is complex and it is impossible to predict outbreaks. Toxic fish (which look, taste and smell normal) contain ciguatoxins derived from microalgae via the food chain. The toxins are not destroyed by cooking and, if consumed in sufficient dose, can cause symptoms persisting for weeks, months or years. The incidence of ciguatera is expected to increase in association with global warming and widespread bleaching and death of coral.

Acute Disease↗

PubMed2000

Topically acquired bacterial zoonoses from fish: a review.

The main pathogens acquired topically from fish (through spine puncture or open wounds) are Aeromonas hydrophila, Edwardsiella tarda, Erysipelothrix rhusiopathiae, Mycobacterium marinum, Streptococcus iniae, Vibrio vulnificus and Vibrio damsela. S. iniae has recently emerged as a public health hazard associated with aquaculture, and M. marinum often infects home aquarium hobbyists. With the expansion of aquaculture and popularity of recreational fishing in Australia, medical practitioners can expect to see more infections of this nature. Diagnosis and treatment may be difficult, especially in view of emerging antibiotic resistance in fish pathogens.

Animals↗

PubMed1993

Risks of fish imports--the 1993 aquatic animal quarantine review.

The rapid expansion of knowledge of fish diseases and pathogens in the past decade has led to a realisation that Australian quarantine policy on fish imports, which has largely evolved on a needs basis, requires substantial revision. As a result, the Australian Quarantine and Inspection Service has commissioned a major review of quarantine policy with regard to risks of disease associated with importation of aquatic animals and their products. The review, to be managed by the Bureau of Resource Sciences, will be carried out this year.

Animals↗