Pathogens and Toxins

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Pathogens and Toxins
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Pathogens

• Prions (Mad Cow, Creuzfeld-Jacob)
• Viruses (Ebola, AIDS, smallpox, common cold)
• Bacteria (cholera, typhoid, plague)
• Protista (malaria, sleeping sickness, Giardia)
• Fungi (athletes foot, yeast infections, Candida)
• Multicellular Organisms (tapeworms, trichinosis,
  schistosomes)

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Viruses

• Viruses are non-living but reproducing
• Viruses invade cells and use cell reproduction
  mechanisms to reproduce
• Retroviruses permanently insert new DNA into cell
  (AIDS)
• Viruses cannot be attacked in cells
• Being non-living, cant be killed by antibiotics
  in blood stream
• Only defenses are immunization or prevention
• Antibiotics do not work against viruses

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Promiscuous Antibiotics

• Used improperly against viral infections
• Essentially given as placebos
• Sugar pills would be more ethical
• Legitimate users do not use properly
• Used as prophylactic measure in factory farms
• Creation of resistant micro-organisms
• Waste antibiotics get into environment

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Chemical Hazards

• Allergens (trigger immune response)
• Neurotoxins (damage nervous system mercury,
  pesticides)
• Mutagens (alter genes)
• Teratogens (cause birth defects alcohol,
  thalidomide)
• Carcinogens (nickel, tobacco, radon)
• Hormone mimics (PCBs)

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Response to Exposure
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Response to Exposure
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Chemicals in Concert

• Antagonistic (Vitamin A, E against carcinogens)
• Additive (Effects combine)
• Synergistic (Effects multiply alcohol drugs,
  smoking asbestos)
• Sensitization or Desensitization

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Factors in Toxicity

• Chemical composition
• Dose
• Acute versus Chronic Exposure
• Solubility and Mobility
• Nature of exposure
• Ability to metabolize, sequester, or excrete
• Tendency to bioaccumulate
• General Health

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Weapons of Mass Destruction

• Weapons capable of inflicting large numbers of
  casualties or affecting a large area in a single
  event
• Nuclear
• Chemical
• Biological
• Any time you pack a large amount of energy into a
  small space, you have a potential weapon

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Chemical Weapons

• Riot Control (Tear Gas)
• Choking (Cl, phosgene CCl2O)
• Blood (HCN)
• Nerve (Sarin)
• Blister (Mustard Gas)
• Hallucinogens (researched, never used)
• Incapacitating (researched, never used)
• Defoliants (Agent Orange, Vietnam)

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Chemical Weapons in War

• World War I
• Tear Gas
• Chlorine
• Mustard Gas
• Japanese in China 1930's - WWII
• Not used by other parties in WWII
• Yemen 1960's
• "Yellow Rain" SE Asia, 1970's (Discredited)
• Iraq against Kurds, Iran, 1980's
• US renounces first use but reserves right to
  retaliate

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Use of Chemical Weapons

• Gases disperse too quickly
• Usually delivered as aerosols
• Dependent on weather conditions
• Wind, rain, heat are unfavorable
• Most historical uses against unprotected targets
• Trained soldiers have protection
• Reduces efficiency of both sides
• Psychological effect

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Effects of Chemical Weapons

• Nerve Agents
• Long Term Nerve Disorders
• Blister Agents
• Short Term Severe Burns
• Long Term Skin Cancers and Lesions, Lung Damage
• Most Chemical Agents Easily Decomposed
• Long Term Effects of Low-Level Exposure Unknown
• Gulf War Syndrome, Agent Orange

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Biological Weapons

• No known modern historical military uses
• US has stated will not use
• Limitations
• Should be self-limiting
• Need fairly quick action
• Anthrax and Smallpox given most speculation
• Plant pathogens
• Wheat Rust, Hoof-and-Mouth
• Drug Interdiction?