- Several types of harmful algal blooms produce toxins that can cause illness in humans through the consumption of contaminated shellfish or fish. These illnesses include Ciguatera Fish Poisoning, Diarrhetic Shellfish Poisoning, Neurotoxic Shellfish Poisoning, Paralytic Shellfish Poisoning, and Amnesic Shellfish Poisoning. - The document outlines the causative organisms, toxins produced, mechanisms of action of the toxins, and symptoms in humans for each of these illnesses. Treatment involves managing symptoms, as there are generally no antidotes for the marine toxins. Prevention strategies include monitoring for algal blooms and providing public education.

10. MICROCYSTIS

11. NODULARIA

17. Ciguatera
Fish
Poisoning
(CFP)

18. Ciguatera Fish Poisoning
 causative organisms:
(Dinoflagellates)
Gambierdiscus toxicus, Prorocentrum
spp., Ostreopsis spp., Cooliamonotis,
cadinium sp. and Amphidinium
carterae
 toxins produced:
Ciguatoxin and maitotoxin

19. Ostreopsis sppGambierdiscus toxicus

20. Ostreopsis ovataGambierdiscus toxicus

21. Ciguatera Fish Poisoning
 Ciguatoxin

22. Ciguatera Fish Poisoning

23. CFP:Vectors
 Usually large fishes, bottom dwellers
and reef fish
 Red snapper,
 Grouper,
 Amber Jack,
 Sturgeon

24. Mechanism of action
 Selective
activation of
voltage-
sensitive
Na+
channels

25. C F P: Symptoms in humans
 Lag time <12 h
 Acute onset
 Early symptoms (24-48 h):
 Gastrointestinal
Pain,cramping,diarrhea,vomiting

26. Late symptoms
 Neurological
 Headache, toothache
 Temperature disturbance
(hot-cold sensation reversal)
 Respiratory paralysis and seizure
In severe cases
 Cardiovascular
Heart rate abnormalities (rare)
arrhythmias

27.  Symptoms usually clear in 1 to 4 weeks
but can last for years.
 Recovery time is variable and may take
weeks, months or years.
 Rapid treatment (within 24 hours) with
MANITOL is reported to relieve some
symptoms.

28. Diarrhetic
Shellfish Poisoning
(DSP)

29. Diarrhetic Shellfish Poisoning
 causative organisms:
(Dinoflagellates)
Dinophysis acuminata, Dinophysis
fortii, Prorocentrum lima
 toxin produced:
Okadaic acids and dinophysistoxins

30. Prorocentrum lima
Dinophysis acuminata

31. Dinophysis acuminata Prorocentrum lima

33. Mechanisms of action
 Inhibits
phosphatase
1 and 2A which
control Na+
secretion from
intestinal cells
 Loss of fluids and
ions from gut
epithelial cells

34. DSP: Symptoms in Humans
 produces gastrointestinal symptoms, usually
beging within 30 min to a few hours after
consumption of toxic shellfish .
 Generally mild gastrointestinal illness
 Diarrhea, nausea, vomiting
 Rapid onset, rapid resolution
 No neurotoxic effects
Long-term effects? (Possibly tumorigenic)
 Recovery occurs within three days, with or without
medical treatment

35. Neurotoxic
Shellfish
Poisoning
(nsp)

36. causative organisms:
Karenia brevis (previously Gymnodinium
breve)
toxins produced: Brevetoxins
Neurotoxic Shellfish Poisoning

38. Karenia brevis

39. Neurotoxic Shellfish
Poisoning

40. Mechanism of action
 Selective
activation of
voltage-
sensitive Na+
channels

41. NSP: Symptoms in human
 Similar to ciguatera poisoning
 Symptom onset ranges from 15 minutes to 18
hours post ingestion, and
 The duration of toxicity ranges from 1-72 hours
(usually < 24 h).
 The brevetoxins, unlike the other shellfish
toxins, can become aerosolized by the surf and
produce an allergic response characterized by
conjunctivitis, bronchospasm, and cough.

42. Early symptoms:
Gastrointestinal
Nausea, diarrhea, vomiting
Late symptoms
Neurological
Tingling
Numbness
Loss of motor control
No deaths have been reported.
recovery is generally complete in a few
days.

43. ParalyticShellfish
Poisoning
(psp)

44.  causative organisms:
(Dinoflagellates)
 Alexandrium spp.
 Gymnodinium spp.
 Pyrodinium spp.
 toxins produced: Saxitoxins
Paralytic Shellfish Poisoning

45. Gymnodinium catenatum

46. Gymnodinium catenatum

47. Saxitoxin

48. Mechanism of action
 Binds and blocks
voltage-
dependent
sodium channels
 Blocks neuron
activity and
affects
peripheral
nervous system

49. PSP: Symptoms in Humans
 PSP, like ASP, is a life threatening syndrome.
 Rapid onset (~30 min)
 Absence of gastrointestinal symptoms
 Neurological symptoms
 Numbness
 Headache
 Weakness
 Cranial nerve dysfunction
 Diaphragmatic paralysis
 Death by asphyxiation
 Weakness can persist for weeks.

50. Amnesic
Shellfish
Poisoning
(ASP)

51. Amnesic Shellfish Poisoning(ASP)
 Causative organisms:
(Diatoms)
Pseudo-nitzschia spp.
 toxin produced:
Domoic Acid

52. Pseudo-nitzschia spp.

53. Pseudo-nitzschia spp.

54. Amnesic Shellfish Poisoning
Domoic Acid

55.  Mimics a
neurotransmitt
er (glutamic
acid)
 Overstimulates
and eventually
kills neurons in
hypocampus
 Stimulates
voltage-
dependent
calcium
channels
Mechanisms of action

56. ASP: Symptoms in Humans
 a life-threatening syndrome.
 It is characterized by both gastrointestinal and
neurological disorders.
Early symptoms:
Gastrointestinal disorder
 Nausea, vomiting, diarrhea, abdominal cramps
In severe cases
Neurological /CNS symptoms
 Dizziness
 headache
 short-term memory loss

57.  respiratory difficulty
coma
Cognitive effects
Disorientation
Seizures
 In the long term cause brain damage.
Sometimes even death, in elderly
patients or patients with impaired kidney
function----Because there is no known
antidote to domoic acid.

58. What can we do about it?
 Prediction
 Satellite tracking of red and brown tides
 Mathematical models predicting blooms
 Prevention
 Public awareness
 Treatment

59. Preventions
 It is important to notify public health departments
about even one person with marine toxin poisoning.
 Investigators can then try to determine if a specific
restaurant, oyster bed, or fishing area has a problem.
This prevents other illnesses.
 In any food poisoning occurrence, consumers should
note foods eaten and freeze any uneaten portions in
case they need to be tested.
 In Hawaii, a commercial test has been developed to
allow persons to test sport-caught fish for ciguatoxins.

60. Guidelines for safe food consumption
 Although anyone eating fish or shellfish but
persons with weakened immune systems or
liver problems should not eat raw seafood
because of their higher risk of infection.
 Seafood should be kept on ice or refrigerated
at less than 38° Fahrenheit to prevent
spoilage .

61. Treatment
 There are no specific treatments for
marine toxin poisoning.
 Treatment generally consists of managing
complications and being supportive until the
illness passes.
 Intravenous MANNITOL has been suggested for
the treatment of severe ciguatera poisoning
 You can also use a sports drink, such as Soda and
fruit juices have sugar and not enough of the
electrolytes that are lost during diarrhea, and they
should not be used to rehydrate.

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ISBN:978-0-12-247990-8
------BOOKS