Transcript ciguatera

Ciguatera Fish Poisoning
Stephanie Perez
Mallery Quetawki
Sara Jones
Introduction
 Gambierdiscus toxicus
 Importance of study
 Macroalgae in coral reefs
 Ciguatoxins
 Reef Fish
 Mechanism
 Ciguatera Fish Poisoning (CFP)
 Epidemiology
 Symptoms, treatment & prognosis
 Prevention
Introduction cont…
 Fun Facts
 Discussion
 Summary
 Extra info
Importance of Study
 G. Toxicus leads to Ciguatera Fish Poisoning in
humans.
 Sea food diners and consumers need to be educated
on risks for exposure to Ciguatoxins
 Disruption of environment, both natural and mancaused, can lead to adverse effects on animals and
humans.
Gambierdiscus toxicus
Photosynthetic benthic dynoflagellates that grow
predominately in association with microalgae in
coral reefs in tropical and subtropical climates
Gambierdiscus toxicus
Found in the Pacific Ocean, Red Sea, Indian Ocean,
and Caribbean Seas from 35°N to 35°S
Gambierdiscus toxicus
Ciguatoxin concentration from G.Toxicus consumption
Gambierdiscus
Toxicus
Small carnivorous
fish
Larger Fish
Humans
Bio accumulated ciguatoxins in the viscera of fish
becomes progressively concentrated upwards along
the food chain
Cycle of Toxin
• Destruction of coral reef ecosystem, due to human activities or
natural events, cause recolonization of microalgae on damaged
surfaces.
• This sparks an outbreak of ciguatera in the damaged regions. The
freshly grown algae is then consumed by smaller fish where the
toxin accumulates in the liver, eggs and skin.
• It is suggested that there maybe chemical alterations of the toxin as it
is metabolized inside these fish as well as the next carnivorous fish
that eats them.
• This process thus causes accumulation and an increase in lethality as
it goes up the food chain.
Tropical/Subtropical Fish
• Moray eel
• Parrot Fish
• Barracuda
• Hogfish
• Grouper
• Coral trout
• Kingfish
• Flowery cod
• Jacks
• Red emperor
• Snapper
• Wrasses
• Surgeonfish
• Spanish Mackerel
All carriers of ciguatoxins in their viscera
Snapper
Flowery Cod
Barracuda
Grouper
Moray Eel
Spanish Mackerel
Ciguatoxin: Info & Mechanism
• Heat stable and are not
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destroyed by cooking, freezing,
or acid
Tasteless & Odorless
Some of the most potent
biological toxins known
Poses a health risk at
concentrations as low as 0.08
to 0.1 μg/kg
Start to exert their effects with
a level of detection at ~0.1
parts per billion.
• Potent heat stable, non-
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protein, lipophilic sodium
channel activator toxin
The poison binds to voltagedependent sodium channels in
muscle and nerve cells, so that
they remain open.
Rest remains unknown
however, other studies suggest
the following:
• Can lead to sensitization
to ciguatoxins in CFP
patients
• the poison inhibits the
action of cholinesterase
Ciguatoxin Type-2 Backbone
Ciguatoxin Type-1 Backbone
Ciguatera Fish Poisoning (CFP)
 Epidemiology
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occurs in 10-50,00 people per year
 incidence rates may be as high as 50 to 500 per
10,000 population per year in the South Pacific region
Mortality is low (0.1 to 4%)
Seasonal differences in occurrence of toxin in ecosystems
Under-reporting occurs in part because individuals with
CFP often do not seek medical attention
Ciguatera poisoning currently poses the largest single
constraint on fisheries development in the eastern
Caribbean
Clinical Signs of Ciguatera
Poisoning
• Symptoms begin 6-12 hours
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after ingestion of fish
Occur in 3 major organ
systems: GI, Neurologic, and
Cardiovascular
First reported symptoms are
usually GI symptoms which last
for a few days after ingestion.
Within the first 3 hours,
Neurological symptoms can be
present and are commonly
moderate to severe.
Cardiovascular symptoms are
reported last and are generally
severe.
Clinical Signs
• Numbness and Tingling in
• Lingual and circumoral
the mouth.
• Abdominal pain, nausea,
vomiting, and diarrhea.
• Dehydration from GI
symptoms
• Dental pain, pruritus,
arhralgias, myalgia,
ataxia, vertigo, and
respiratory paralysis may
also be observed.
paresthesis, painful
paresthesias of the
extremities, and
paradoxical temperature
reversal (reversal of hot
and cold sensation).
• Coma, bradycardia, and
hypotension can be seen
in extremely severe cases.
Diagnosis
• Although Ciguatera Fish
Poisoning is the most
commonly reported
seafood illness in the
world, doctors do not have
a human biomarker to
confirm Ciguarta fish
posioning.
• All diagnosis are
based on clincal signs
and observation of the
patient. (Friedman, M.A.
et al 2008)
• A proper diagnosis is made
by looking at the time line
of the symptoms and type
of fish consumed.
• Must rule out other
illnesses (mostly shellfish
poisonings or multiple
sclerosis) which exhibit
similar symptoms.
Diagnosis
• Current research is
looking into detecting the
presence of ciguatoxin in
human blood or serum
which could be a future
diagnostic tool.
• This research is looking
into using ELISA
bioassays for use of
detection.
• The most accurate
diagnosis is made after
the timeline of symptoms
has been checked and
verified with symptoms
seen with ciguatera fish
poisoning. If a sample is
present, testing the
viscera of the fish for the
ciguatoxin will give the
most accurate diagnosis.
Treatment
• Due to the absence of a
concrete method of
diagnosing an actual
case of CFP, it is hard to
research new drug
treatments. The lack of
accurate diagnosis
paired with the sporadic
cases makes clinical
research for therapeutic
drugs very difficult.
• Currently, Mannitol is
the main drug used for
Ciguatoxin cases as it is
the most widely studied.
However, it is the only
drug therapy that has
shown promise in
clinical studies.
Treatment
• The main course of
• Charcoal can help with GI
decontamination. It only
treatment is to treat the
works if it is administered
symptoms.
within 3-4 hours of the
• Treatment varies on the
initial ingestion.
symptoms as the
• Antiemetics may control
poisoning presents
nausea and vomiting.
different signs in
different patients.
• Cold showers and
antihistamines can help
with pain from pruritus.
Medications
 There are six different kinds of medicines that are
most affective in treating CFP.
 They are: neurologic agents, serotoninnorepinephrine reuptake inhibitors, antihistamines,
analgesics, antipyretics, and anti-inflammatories
Medications
 ANTIHISTAMINES
 Mainly used to relieve
pruritus (itching)
 Diphenhydramine
(Benadryl)
 It is the main treatment
for pruritus as it blocks
histamine release.
 Hydroxyzine (Atarax)
 Antagonizes H1
receptors in periphery.
May suppress
histamine activity in
subcortical region of
CNS. It is another
pruritus treatment.
 Cyproheptadine
 used to treat pruritus.
Unknown mechanism
Medications
• SEROTONIN/NOREPINE
PHRINE REUPTAKE
INHIBITORS
• The inhibitors block the
active reuptake of
norepinephirne and
serotonin.
• Have central and
peripheral
anticholingeric and
sedative effects.
• Amitriptyline is
commonly used to
relieve pruritus and
dysesthesias.
• It is most effective for
chronic neurologic
symptoms.
• Blocks Na+ channels
that were activated by
the ciguatoxinn
Medications
• ANALGESICS
• Used for pain relief
• Acetaminophen and
Paracetamol are most
commonly used.
• Indomethacin (Indocin)
• used to relieve myalgias
and arthralgias.
• DIURETICS, OSMOTICS
• These medications treat
neurological signs. They
have been proven to
relieve neurological
symptoms within 2 days
(Mitchell, G. et al. 2005).
• Mannitol is the main
osmotic diuretic used for
treatment of neurological
symptoms.
Mannitol
• Previously, Mannitol was
only used for acute
neurological symptoms.
• Recent studies have
shown that Mannitol has
beneficial effects on mild
to moderate cases as well.
(Mitchell, G. 2005)
• Mannitol is primarily used
to lessen the severity of
acute cases and to prevent
the onset of chronic
neurologic symptoms.
• Mannitol is administered
through IV and should be
administered within 2-3
days after ingestion of
toxic fish.
• Precautions must be taken
when administering
Mannitol as it can cause
further dehydration in
patients suffering from
severe vomiting and
diarrhea.
Mannitol
• The exact mechanism is
unknown, but it is
thought to be mediated
by the osmotic
reduction of neuronal
edema caused by the
increase of sodium and
ultimate depolarization
of the nerve cell.
• Mannitol may inhibit
the reaction of the
ciguatoxin at the
sodium and potassium
channels thus
deactivating the voltage
gated sodium channels
in the cell membranes.
Prognosis
• In almost all cases, the
patient will make a full
recovery.
• Ciguatera poisoning has
extremely low mortality
rates ~ 0.1%
• Most deaths are attributed
to severe cases and are
caused by severe
dehydration,
cardiovascular shock, or
respiratory paralysis.
• The patient will feel weak
and lethargic for a period
of a week up to a month
after infection.
• In some cases, chronic
neurologic symptoms may
remain for months and in
some cases, years. These
cases have not been
studied at length. Future
studies will focus on this
topic.
Prognosis
• Increased sensitivity to
the toxin has been noted
in some cases.
• Patients who had a past
bout of CFP experienced a
reoccurrence of ciguatera
poisoning after eating a
ciguateraic fish when
other people who ate it
showed no symptoms.
• Ingestion of fish, shellfish,
alcohol, nuts, Opiates, and
Barbiturates have been
reported to intensify the
symptoms among patients
who are recovering from
CFP.
• These same products can
also cause a reoccurrence
of neurological symptoms
years later.
• The exact reason for this
is unknown
Prevention
• Home products are
available and are able to
test if ciguatoxin is present
in fish that are cooked.
However, there is
insufficient data available to
show if these products are
effective or not.
• If you think you may have
ciguatera poisoning, report
your symptoms and what
fish you ate to your doctor,
local emergency room, or
health department. If
possible, save meal
remnants.
Prevention
• Knowledge is your best prevention.
• The next best preventative
measure is to stop or reduce
destruction of coral reefs which
lead to G. Toxicus accumulation.
• Educate yourself about seafood
fish posioning. Know what types of
fish are vectors for the ciguatoxin
and be sure you know where it
came from if you are planning on
consuming reef fish.
• Florida has an aquatic toxins
program to teach their residents
about the dangers of seafood
poisoning.
http://www.myfloridaeh.com/med
icine/aquatic/index.html
Fun Facts: Folk Science
 If no flies on fish= +CFP
 Feed fish to cat and the
cat vomits= +CFP
Discussion
 There is a need for protection of aquatic habitats so
that G. toxicus does not disperse.
 There is further research needed to find how
ciguatoxins effect animal and human physiology.
 Greater knowledge about this will lead to better
diagnostic techniques, drug therapies, and treatment
plans.
 Further studies should focus on how and why toxin is
produced during disturbance of coral reef.
Discussion
 Questions remain:
 If other toxins can be used in a
variety of other ways, is it true
to say that G. toxicus can be
used for other things such as
pesticides, cosmetics or
everyday housecleaning
agents?
 What is the exact mechanism
that the toxin undergoes in the
fish to cause it to accumulate in
the tissues?
 What other health effects does
it have on humans?
 Will we ever find a proper
method for testing for and
preventing spread of
ciguatoxins?
 Does ciguatoxin have any
biomedical uses?
 How can fish avoid eating the
toxic algae?
 Do fish feel the same symptoms
as humans?
Discussion
 Is this toxin produced as a defense
mechanism for G. toxicus although a
majority of the fish do not seem to exhibit
side effects from exposure?
 Could fish use this toxin, if not harmed by it, for use against predation?
 At what costs are the toxin made?
 Even disruption from natural disasters causes
accumulation of toxin in damaged areas of reef.
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Better dispersal method since natural disturbances are common?
Summary
• G. toxicus emerges from
disrupted ocean beds and
reefs, concluding that
oceanic ecosystem
destruction causes harm to
animals and humans via
dispersal of toxin.
• When herbivore fish ingest
G. toxicus they accumulate
in organs and tissues as well
as in the next predator fish
that consumes them.
• Humans are ailed with
Ciguatera Fish Poisoning
upon ingestion of infected
fish.
• Symptoms of illness varies
across individuals.
• Mannitol is best treatment
available.
• Prevention is key
• Know where your fish are
coming from and reduce
oceanic ecosystem
destruction.
• Further study must be done
to understand
bioaccumulation of toxin as
well as its mechanism in
humans.
Videos
 Watch interviews on CFP encounters/symptoms.
(8mins)
YouTube - Ciguatera Interviews
 Other video on CFP testing if interested (10mins):
http://www.youtube.com/watch?v=rbdEBUiXKV0
References
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