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 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

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 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 Riot Control (Tear Gas) Choking (Cl, phosgene CCl 2 O) 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 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?