Pfiesteria Toxin and Learning Performance

Levin, Edward D.; Simon, Barbara B.; Schmechel, Donald E.; Glasgow, Howard B.; Deamer-Melia, Nora J.; Burkholder, JoAnn M.; Moser, Virginia C.; Jensen, Karl F.; Harry, G. Jean

doi:10.1016/s0892-0362(98)00041-5

Cited by 37 publications

(41 citation statements)

References 10 publications

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“…For example, children (40) and the elderly (41) are thought to be more susceptible to development of some neurotoxicantinduced effects than younger adults, and may be more susceptible to developing PEAS. However, the nonspecific symptoms of PEAS, such as deceased short-term memory, concentration difficulty and/or confusion (8), and the learning or attention effects observed in a rodent model of PEAS (9)(10)(11), overlap with the symptoms observed in commonly diagnosed syndromes in children and aged adults associated with learning disability and dementia conditions, respectively. Only a few of the reported PEAS patients attributed their symptoms to estuarine contact.…”

Section: Discussionmentioning

confidence: 99%

“…Performance among the most severely affected participants returned to within normal limits in 3-6 months following estuarine contact, although the completeness of recovery and possible effects of ancillary treatments were undetermined (8). Learning or attention deficits have also been observed in rodents injected with water from tanks in which TPC had been activated to kill fish (9)(10)(11).…”

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confidence: 99%

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Residential and recreational acquisition of possible estuary-associated syndrome: a new approach to successful diagnosis and treatment.

Shoemaker

2001

Environ Health Perspect

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Evidence suggests that the estuarine dinoflagellates, Pfiesteria piscicida Steidinger & Burkholder and P. shumwayae Glasgow & Burkholder, members of the toxic Pfiesteria complex (TPC), may release one or more toxins that kill fish and adversely affect human health. In the current study we investigated the potential for undiagnosed cases of possible estuary-associated syndrome (PEAS), as termed by the Centers for Disease Control and Prevention (CDC), in a population that had residential and/or recreational exposure to TPC-affected estuaries, but that did not have direct contact with fish kills or lesioned fish. Age-adjusted visual contrast sensitivity (VCS) was significantly lower and the presence of PEAS-associated symptoms was much higher in the estuary cohort (n = 77) than in combined-control cohorts (n = 87), one without exposure to bodies of water (n = 53) and one with exposure to marine waters (n = 34). In the estuary cohort, 37 individuals met the CDC case definition for PEAS and had significantly lower VCS than non-PEAS cases. The VCS improved and symptoms abated after 2 weeks of treatment with cholestyramine. Cholestyramine, the original drug approved for treatment of hypercholesterolemia, has previously been reported to enhance the elimination rates of a variety of toxins, presumably by interruption of enterohepatic recirculation through toxin entrapment in its polymeric structure and/or anion-exchange process. Control studies showed that repeated VCS testing alone did not improve VCS scores and that cholestyramine treatment did not affect VCS in patients with elevated cholesterol levels. These results suggested that a) susceptible individuals may acquire PEAS through residential and/or recreational contact with TPC-affected estuaries in the absence of an active fish kill; b) VCS is a useful indicator in PEAS diagnosis and treatment monitoring; and c) PEAS can be effectively treated with cholestyramine. Because the study did not use population sampling techniques, the results do not indicate PEAS prevalence. Furthermore, definitive diagnosis of PEAS and association with TPC toxin(s) must await identification of, and a serologic test for, the putative TPC toxin(s).

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Residential and recreational acquisition of possible estuary-associated syndrome: a new approach to successful diagnosis and treatment.

Shoemaker

2001

Environ Health Perspect

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“…The potentially transient nature of symptoms associated with the syndrome is also indirectly supported by the lack of evidence for marked, consistent deficits in a North Carolina cohort studied 2-3 months after the last recognized fish kill involving Pfiesteria (4). Finally, learning and processing difficulties in rats exposed to extracts of the Pfiesteria toxin have also been reported (5,6), and these effects were also thought to be dose responsive. Overall, the present state of knowledge suggests that exposure to P. piscicida can result in a mild, transient encephalopathy primarily affecting learning and memory and higher-order executive functions.…”

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confidence: 97%

Potential human health effects associated with laboratory exposures to Pfiesteria piscicida.

Schmechel

Koltai

2001

Environ Health Perspect

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The adverse human health effects associated with the most prolonged and intense exposure known to Pfiesteria piscicida Steidinger & Burkholder cultures and toxin(s) are described. In December 1993, a patient presented with acute illness to the Memory Disorders Clinic of the Bryan Alzheimer's Disease Research Center at Duke University Medical Center with significant cognitive deficits 2 weeks after ceasing occupational laboratory exposure on the recommendation of the evaluating primary care physician. The clinical and exposure histories of this patient are presented. The comprehensive neurological examination findings are reviewed, with attention to the patient's neuropsychological evaluation. Six-week follow-up data illustrate the course of symptom resolution with exposure cessation. This case is presented in an effort to contribute to the gradually accruing evidence of potential central nervous system sequelae of Pfiesteria exposure. The case is discussed in the context of additional cases evaluated at Duke University Medical Center and the complicated scientific framework in which such evaluations proceed while definitive surrogate or biological markers are awaited.

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“…Behavioral changes were reported in rats exposed to extracts from Pfiesteria culture water (81)(82)(83). These behavioral changes suggest impairment of central nervous system functioning in these animals.…”

Section: Clinical Assessment and Neurotoxicologymentioning

confidence: 98%

“…It is not clear, however, whether this instability is due to chemical degradation, adsorption to surfaces, metabolism, or other factors. Sterile aquarium water filtrate has been shown to be nonlethal to fish after 48 hr at ambient room temperature (11,38), but water samples stored frozen retain toxic activity in rats through at least one freeze-thaw cycle (58,59). Lipophilic toxin fractions adsorbed to C-18 chromatography resin and eluted with acetonitrile retained potent cytotoxicity (60).…”

Section: Chemical Properties Of Pfiesteria Toxinmentioning

confidence: 99%

Pfiesteria: Review of the Science and Identification of Research Gaps. Report for the National Center for Environmental Health, Centers for Disease Control and Prevention

Samet¹,

Bignami²,

Feldman³

et al. 2001

Environmental Health Perspectives

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The Pfiesteria organism was first identified and named in the early 1990s and its ability to kill fish was documented at the time. Research on the effects of exposure to its toxin on humans is more recent, sparked largely by widely publicized fish kills in the late 1990s and reports of adversely affected persons present at the scenes of the kills. Consequently, the peer-reviewed literature is still limited and substantial research is in progress at institutions in the Atlantic coast states of Maryland, North Carolina, and Virginia, and elsewhere. Dramatic reports of fish kills and illness among persons exposed to water at the time of the kills sparked public concern and reviews by a variety of agencies in the late 1990s. The primary data sources, secondary reviews, and expert panel reports were evaluated by this panel.In approaching its charge, the panel turned to a toxicologically based framework for conducting its review, characterizing the state of the science, and identifying research gaps (Figure 1). Prevention of adverse effects of Pfiesteria will need to be based in an understanding of each element in this framework: the ecological factors that drive concentrations of the organism and its state; the stimuli that lead to toxin production and the nature of the toxin; the mechanism of the toxin's effect on fish; the circumstances and routes of human exposure; and the mechanisms by which human health is adversely affected by the toxin. Sufficient certainty is needed on each of these points to evolve policies that will assure protection of public health and the fish populations. In addition, we need enhanced understanding of the still poorly characterized effects of Pfiesteria on human health.Other reviewers have commented on many elements of this framework; their reviews make clear that there are gaps in scientific understanding, with attendant uncertainty for decision makers, for each of these elements. With substantial research now under way, the panel views the timing of this review as an opportunity to examine the gaps and the extent to which new research findings will set aside uncertainties.Pfiesteria has proved to be a challenging problem. Researchers have referred to the organism as "ephemeral" and "phantom-like."It has multiple forms, transforming itself into a toxin-producing dinoflagellate when it somehow senses the presence of fish. Its toxin apparently destroys the integrity of the skin of fish, allowing the organism to feed; after feeding, the organism transforms into a dormant form. (Throughout this report, we refer to "Pfiesteria toxin," recognizing that the organism may well produce more than one toxin. We use the plural "toxins" in describing the basis for supposing that more than one toxin exists.) There is debate as to whether a pathognomonic lesion occurs in fish. Humans seem to be at risk when their activities lead to contact with toxin-containing water at the time of fish kills. Whether the toxin reaches target tissues by dermal contact or inhalation is unclear. A diffuse syndrome has b...

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Pfiesteria Toxin and Learning Performance

Cited by 37 publications

References 10 publications

Residential and recreational acquisition of possible estuary-associated syndrome: a new approach to successful diagnosis and treatment.

Residential and recreational acquisition of possible estuary-associated syndrome: a new approach to successful diagnosis and treatment.

Potential human health effects associated with laboratory exposures to Pfiesteria piscicida.

Pfiesteria: Review of the Science and Identification of Research Gaps. Report for the National Center for Environmental Health, Centers for Disease Control and Prevention

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