Chapter 109

1. Chapter 109 Potential Weapons of Biologic, Radiologic, and Chemical Terrorism

2. Potential Weapons of Terrorism • Bacteria • Viruses • Biotoxins • Chemical weapons • Nerve agents and mustard gas • Radiologic weapons

4. Bacteria and Viruses • Anthrax • Bacillus anthracis • Aerobic gram-positive bacterium • Dormant form viable for decades • Inhalational, cutaneous, gastrointestinal • Enters the body via the skin or mucous membranes of the respiratory tract • Not transmitted person to person

5. Inhalational Anthrax • Anthrax spores deposit in alveolar space • Even with treatment, mortality can be high • Clinical latency 2 days-4 weeks • Mature bacilli release toxins • Hemorrhage, edema, and necrosis • If toxins reach critical level, antibiotics cannot prevent death • Initial symptoms • Fever, cough, malaise, weakness • Second stage (2-3 days later) • Sudden increase in fever, severe respiratory distress, septicemia, hemorrhagic meningitis, and shock

6. Cutaneous Anthrax • Symptoms 1-7 days after exposure to spores • Broken skin most vulnerable • Injury can develop anywhere spores land • Initial lesion – small papule or vesicle associated with local itching • 2 days – lesion enlarges into painless ulcer with necrotic core • 7-10 days after symptoms – black eschar forms, then dries, loosens, and sloughs off by days 12-14 • In most cases lesions resolve without complications or scarring • Treatment is usually successful, but 20% die without antibiotic treatment

7. Treatment of Anthrax Infection • Respiratory • IV ciprofloxacin • IV doxycycline • Cutaneous • Oral ciprofloxacin • Oral doxycycline

8. Pre-Exposure Vaccination • BioThrax (formerly known as Anthrax Vaccine Adsorbed, or AVA) • Licensed for use in U.S. • Inactivated cell-free preparation • 3 subQ injections 2 weeks apart, then at 6, 12, and 18 months • Persons at high risk should be vaccinated • Military personnel, those who handle animal products from anthrax-endemic areas, including veterinarians, lab workers, others

9. Postexposure Prophylaxis • Oral antibiotics + anthrax vaccine • Vaccine at 0, 2, and 4 weeks • BioThrax not currently licensed for postexposure

10. Francisella tularensis (Tularemia) “Rabbit Fever” and “Deer Fly Fever” • Potentially fatal • Skin, mucous membranes, GI tract, or lungs • Acute flu-like symptoms initially • Pneumonia and pleuritis can develop • Treatment • IM streptomycin, gentamicin • Mass outbreak – oral doxycycline or ciprofloxacin

11. Pneumonic Plague • Transmitted person to person • Acquired by inhaling aerosolized Yersinia pestis • With no treatment, rapidly progresses to respiratory failure and death • Treatment is streptomycin (IM) and gentamicin (IM or IV)

12. Smallpox • No proven treatment • Highly contagious; fatality rate 30% • ACAM2000 approved vaccine • Imvamune (in clinical trials) • Vaccine produces high level of immunity for 5 to 10 years (before exposure or within a few days of exposure) • Pathogenesis and clinical manifestations • Transmission

13. Smallpox Vaccine • Adverse effects • Mild effects • Local inflammation, along with swelling and tenderness in regional lymph nodes • Transient symptoms (fever, headache, muscle aches, fatigue) • Moderate to severe • Eczema vaccinatum, generalized vaccinia, progressive vaccinia, postvaccinial encephalitis, fetal vaccinia, possible cardiac effects • Who should not be vaccinated? • Persons with eczema, atopic dermatitis, immunodeficiency, pregnancy • Persons living with someone else

14. Biotoxins • Botulinum toxin • Clostridium botulinum • Blocks release of acetylcholine from cholinergic neurons • With no treatment, rapidly progresses to paralysis and respiratory failure and death • Classic symptoms – double vision, blurred vision, drooping eyelids, slurred speech, dry mouth, dysphagia, muscle weakness, descending flaccid paralysis

15. Botulinum Toxin • Treatment • Prolonged supportive care • Fluid/nutritional support • Mechanical ventilation • Immediate infusion of botulinum antitoxin

16. Ricin • Toxin present in castor beans • Extraction from the “mash” when beans are processed to make castor oil • Powder, pellet, mist, or dissolved in water or a weak acid • Inhibits protein synthesis • Treatment is purely supportive • No antidote for ricin • Vaccine in development

17. Ricin: Clinical Manifestations • Inhalation • Few hours – coughing, chest tightness, difficulty breathing, nausea, muscle aches • Later – severely inflamed/edematous airway; cyanosis and death can follow • Ingestion • Intestinal and gastric hemorrhage, vomiting, diarrhea; then liver, spleen, kidneys may fail; death within 10-12 days of ingestion • Injection • Severe symptoms and death; impractical route for terrorism

18. Chemical Weapons • Nerve agents • Produce a state of cholinergic crisis, characterized by excessive muscarinic stimulation and depolarizing neuromuscular blockade • Treatment – mechanical ventilation, atropine, and diazepam

19. Chemical Weapons • Sulfur mustard (mustard gas) • Alkylating agent and vesicant • Can be vaporized into air or released into water supply • Injuries severe, but fatality rate is low • During WWI – killed less than 5% of victims

20. Radiologic Weapons • Nuclear bombs • Immediate and delayed impact • Nuclear power plant attack • Radiation exposure in area • Dirty bombs (radiologic dispersion devices) • Radioactive material formulated into powder or pellets

21. Drugs for Radiation Emergencies • Potassium iodide • Prompt treatment necessary • Penetrate zinc trisodium and penetrate calcium trisodium • Treatment within 24 hours most effective • Prussian blue (Radiogardase)