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 ...

travel.webshots.com/photo

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

Ciguatera Intoxication

◗  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

Ciguatera

Plankton - Dinoflagellates

Reef Fish - Snapper http://www.missbonita2.com/

www.botany.ut.ee

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 [25] Queensland, Australia 3 1965–1984 Gillespie 1986 [4] Hawaii 0.3 1975–1981 Anderson 1983 [96] US Virgin Islands 7.6 1982 Morris 1982 [97] Guadeloupe 30 1984 Czernichow 1984 [98] South Pacific Region 970 1973–1983 Lewis 1986 [99] Marshall Islands 2,820 1982–1983 Lewis 1986 [99] French Polynesia 5,850 1979–1983 Lewis 1986 [99] Dade County, FL 5 1974–1976 Lawrence 1980 Culebra, Puerto Rico 73.6–169.5 2005–2006 Luber, In prep [100]

Geographic Region Prevalence (%) Time range Citation US Virgin Islands 4.4 Annual (1980) McMillan 1980 [101] Puerto Rico 7 Lifetime Holt 1984 [102] Tahiti 8.45 Annual (1966) Bagnis 1979 [16] Hao (Tuamotos) 43 Annual (1978) Lewis 1986 [99] Polynesian Islands 70 Lifetime Lewis 1986 [99]

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

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Eat me … you lose

www.informaction.org

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)

www.chemgapedia.de

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

Red Tide

pathtosustainable.wordpress.com

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

www.orhab.org/education/Pseudo_nitzschia_sp.htm

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)

http://www.uncwil.edu/riverrun/river_tutorial/12pfiesteria.jpg www.whoi.edu/.../pfiesteriafishsores.html

‘Ambush’ or ‘Predator’ Dinoflagellates

◗  Dinofl