Marine Toxins & Intoxications - Groupe Santأ© Marine Toxins & Intoxications Brian J Ward JD...
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Transcript of Marine Toxins & Intoxications - Groupe Santأ© Marine Toxins & Intoxications Brian J Ward JD...
Marine Toxins & Intoxications Brian J Ward
JD MacLean Centre for Tropical Diseases
Colloque Blue 2012
Overview of talk ◗ Toxins
• fish (eg: ciguatera scromboid) • shellfish (eg: domoic acid) • phyto/zooplankton
◗ Stings/envenomations • vertebrates (eg: rays, lionfish) • invertebrates (eg: jellys, cones,corals) • phyto/zooplankton
You Never Really Know Who You’ll be Sharing the Water With ...
Toxins & Intoxications
◗ Fish • ciguatera • scromboid • puffer fish
◗ Shellfish • PSP, DSP, ASP, etc
◗ Phyto/zooplankton • Pfisteria spp
◗ Amnesic Shellfish Poisoning (ASP) ◗ Paralytic Shellfish Poisoning (PSP) ◗ Neurotoxic Shellfish Poisoning (PSP) ◗ Ciguatera Fish Poisoning (CFP) ◗ Diarrhetic Shellfish Poisoning (DSP) ◗ Pfiesteria Intoxication
Human Illnesses Associated with Marine & Estuarine Plankton
◗ Ingestion of bioaccumulated dinoflagellate toxins in tropical reef fish (snapper, barracuda….)
◗ Dinoflagellate species (various) • Gambierdiscus toxicus, Prorocentrum spp.,
Amphidinium.spp. ◗ Major Toxins
• Ciguatoxin --opens voltage dependent Na channels • Maitotoxin --Calcium channel activator
Plankton - Dinoflagellates
Reef Fish - Snapper http://www.missbonita2.com/
Ciguatera Incidence/Prevalence Reported Incidence and Prevalence of CFP
Geographic Region Incidence/10,000/year Data time period Reference Reunion Island 0.78 1986–1994 Quod 1996  Queensland, Australia 3 1965–1984 Gillespie 1986  Hawaii 0.3 1975–1981 Anderson 1983  US Virgin Islands 7.6 1982 Morris 1982  Guadeloupe 30 1984 Czernichow 1984  South Pacific Region 970 1973–1983 Lewis 1986  Marshall Islands 2,820 1982–1983 Lewis 1986  French Polynesia 5,850 1979–1983 Lewis 1986  Dade County, FL 5 1974–1976 Lawrence 1980 Culebra, Puerto Rico 73.6–169.5 2005–2006 Luber, In prep 
Geographic Region Prevalence (%) Time range Citation US Virgin Islands 4.4 Annual (1980) McMillan 1980  Puerto Rico 7 Lifetime Holt 1984  Tahiti 8.45 Annual (1966) Bagnis 1979  Hao (Tuamotos) 43 Annual (1978) Lewis 1986  Polynesian Islands 70 Lifetime Lewis 1986 
Mar Drugs. 2008 September; 6(3): 456–479.
Ciguarera - Clinical Presentation
◗ Constellation of neurologic, GI, and cardiovascular symptoms • nausea, vomiting, diarrhea • paresthesias, headache, numbness, weakness • (paralysis and coma may ensue) • arrhythmias, hypotension, brady/tachycardia
◗ Neurologic Sx: median duration 2-3 weeks, but chronic or relapsing syndromes can occur for years
Reef Russian Roulette
Eat me … you lose
Treatment ◗ IV mannitol (0.5-1 g/kg over 30-45 minutes)
• Little convincing evidence of benefit • Little risk • Very little evidence of effect >72 hours
◗ Avoidance of certain foods (idiosyncratic) including fish, alcohol, nuts, caffeine, pork … ◗ Supportive
Mar Drugs. 2008 September; 6(3): 456–479.
Mattei C et al. Brevenal inhibits pacific ciguatoxin-1B-induced neurosecretion from bovine chromaffin cells. PLoS One. 2008;3(10):e3448. Epub 2008 Oct 20.
Department of Fisheries and Oceans, the Canadian Food Inspection Agency and Environment Canada
Executive Summary Consumer Awareness and Perceptions of Shellfish Consumption and Recreational Harvesting: Findings from the Baseline Survey Prepared for Canadian Food Inspection Agency December 15, 2006
• Telephone survey 1400 (390 coastal): 37% of non-coastal visited coast(s)
• 27% had eaten shellfish harvested by themselves: 9% in last 12 months
• 10% had bought shellfish from the back of a truck and 10% from fisherman
• 70% thought all shellfish sold in Canada is safe
• 16% thought shellfish caught by themselves or friends might be unsafe
• Most thought that ‘pollution was the main risk (23% said mercury)
• 54% didn’t think that eating any shellfish was a serious risk for healthy adults
• 70% believe shellfish are safe after cooking
Canadian Shellfish Sanitation Program (CSSP)
Paralytic Shellfish Poisoning
◗ Ingestion of bioaccumulated dinoflagellate toxins in shellfish (mussels, clams, oysters….)
◗ Dinoflagellate species • Alexandrium spp • Gonyaulax spp
◗ Major Toxins: • Saxitoxins: Voltage dependent • Na channel blockade (extremely potent toxins)
PSP - clinical presentation
◗ Predominantly neurologic syndrome: tingling, burning, numbness, drowsiness, dysarthria, and paralysis: can be life-threatening.
◗ Signs & symptoms usually appear within ~one hour of eating contaminated shellfish
◗ Residual sequelae uncommon ◗ Prevention through shellfish monitoring
Eutrophication ◗ an increase in chemical
nutrients in an ecosystem to an extent that increases the primary productivity of the ecosystem.
Neurotoxic Shellfish Poisoning ◗ Ingestion of bioaccumulated dinoflagellate toxins
in shellfish (bivalves). Rarely, aerosol exposure to toxins
◗ Dinoflagellate: Karenia breve (Gymnodinium) ◗ Toxin:
• brevetoxins: linear polycyclic ethers • (similar structure to ciguatoxins) • Voltage dependent Na channel activation
NSP - Clinical presentation ◗ Clinical symptoms include both neurologic
and gastrointestinal effects: • circumoral paresthesias, dizziness, ataxia • nausea, abdominal pain, vomiting, diarrhea • respiratory symptoms with aerosol exposure
◗ Clinical onset within minutes to hours; recovery usually complete.
◗ Prevention: monitoring G. breve counts Errera RM et al. Variation in brevetoxin and brevenal content among clonal cultures of Karenia brevis may influence bloom toxicity. Toxicon. 2010 Feb-Mar;55(2-3):195-203
Bivalves - Natures Filters
Filter-concentration of up to 40 GALLONS of water per day
• Plankton toxins • Hepatitis A • Polio (?) • Other viruses (?) • Cholera • Cryptosporidium
Diarrhetic Shellfish Poisoning
◗ Ingestion of bioaccumulated dinoflagellate toxin in shellfish (mussels, scallops, clams.)
◗ (Japan, Europe. Not reported in U.S.) ◗ Dinophysis fortii, D. acuminata ◗ Toxin: okadaic acid
• polycyclic ether compound • protein phosphatase 1 & 2A inhibitor
DSP - Clinical presentation
◗ DSP produces gastrointestinal symptoms, usually within 30 minutes of consumption of contaminated shellfish.
◗ Diarrhea (may be incapacitating), nausea, vomiting, abdominal cramps, chills.
◗ Recovery within 2-3 days, with or without treatment. No sequelae identified
Amnestic Shellfish Poisoning ◗ Ingestion of bioaccumulated diatom toxins in
shellfish (mussels, clams, oysters..) ◗ Nitzschia pungens & Pseudo-nitzchia sp ◗ Recognized outbreaks: Maritime Canada, U.S.
northern Atlantic & Pacific coasts ◗ Toxin: domoic acid (water soluble)
• structurally related to the excitatory amino acid neurotransmitter glutamic acid
ASP - Clinical presentation
◗ Life-threatening disorder with both gastrointestinal and neurologic symptoms
◗ GI: nausea, vomiting, diarrhea, cramps ◗ Neurological: dizziness, headache, seizures,
diorientation, short-term memory loss, coma • information encoding, generally intact • delayed recall significantly impaired • hippocampal & amygdaloid nucleus necosis
ASP - Clinical presentation II
◗ Disease most severe in the elderly and those with renal impairment.
◗ Among survivors, sequelae may include significant memory deficits and motor neuropathy
◗ Prevention through water and shellfish monitoring (diatom counts, toxin assays)
Pfiesteria piscicida ◗ 1988 - cause of fish deaths in aquaria at North
Carolina University Veterinary School ◗ 1991 - cause of natural habitat fish kills in the
estuarine system of North Carolina. ◗ Since then, repeatedly identified as a cause of fish
kills in North Carolina (106-109 fish)
‘Ambush’ or ‘Predator’ Dinoflagellates