Transcript Pathogens and Toxins

Pathogens and Toxins
Pathogens
• Prions (Mad Cow, Creuzfeld-Jacob)
• Viruses (Ebola, AIDS, smallpox, common
cold)
• Bacteria (cholera, typhoid, plague)
• Protista (malaria, sleeping sickness,
Giardia)
• Fungi (athlete’s foot, yeast infections,
Candida)
• Multicellular Organisms (tapeworms,
trichinosis, schistosomes)
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, can’t be killed by antibiotics in
blood stream
• Only defenses are immunization or prevention
• Antibiotics do not work against viruses
Promiscuous Antibiotics
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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
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 (PCB’s)
Response to Exposure
Response to Exposure
Chemicals in Concert
• Antagonistic (Vitamin A, E against
carcinogens)
• Additive (Effects combine)
• Synergistic (Effects multiply: alcohol +
drugs, smoking + asbestos)
• Sensitization or Desensitization
Factors in Toxicity
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Chemical composition
Dose
Acute versus Chronic Exposure
Solubility and Mobility
Nature of exposure
Ability to metabolize, sequester, or excrete
Tendency to bioaccumulate
General Health
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
Chemical Weapons
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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)
Chemical Weapons in War
• World War I
– Tear Gas
– Chlorine
– Mustard Gas
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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
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
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
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?