Bioterrorism and Biowarfare

Considerations

The aims of bioterrorism and biowarfare are

• inflict maximum casualties
• instill fear
• disrupt normal operations
• incapacitate as many people as possible
• cause economic damage

Pathogens and agents of particular concern therefore are those which

• have high infectivity
• have a low ID50
• are virulent
• have a high morbidity
• have a high mortality
• can be transmitted person-to-person
• can be spread easily
  • water-borne
  • airborne
  • food-borne

Accordingly, these agents are classified into 3 categories

1. Category A: 
   • anthrax: persistance, ID50 ~ 10,000 spores, mortality ~ 45%
   • botulism: extremely poisonous; food supply
   • plague: ID ~ 100 - 500, airborne transmission, mortality up to 90% (untreated)
   • tularemia: ID ~ 10-50; mortality 8%/<1%
   • smallpox: person-person transmission, lack of treatment, mortality ~ 30%, ID50 ~ 10-100
   • VHF: mortality up to 90%; fear factor
2. Category B: 
   • Psittacosis: mortality <1% if treated; airborne, chronic infections
   • Brucellosis: aerosol (ID ~10-100) and food spread; mortality 1-2 %; chronic infections
   • Q fever: ID 1 - 10, aerosol spread, resistant; mortality ~ 1%
   • Typhus fever: ID ~10, mortality 3-4% treated
   • Melioidosis (Burkholderia): 20% (treatment in ICU) to 90% (untreated) mortality
   • food threats
   • water threats
   • encephalitis viruses
   • toxins
3. Category C: emerging diseases
   • Nipah
   • Hanta

In what important ways does the epidemiology of bioterror agents differ from that of ordinary infectious diseases?

Bioterrorism agents

Bacteria

1. Bacillus anthracis (anthrax)
2. Brucella species (brucellosis)
3. Burkholderia mallei (glanders)
4. Burkholderia pseudomallei (melioidosis)
5. Chlamydia psittaci (psittacosis)
6. Cholera (Vibrio cholerae)
7. Clostridium botulinum toxin (botulism)
8. Coxiella burnetii (Q fever)
9. Escherichia coli O157:H7 (E. coli)
10. Francisella tularensis (tularemia)
11. Rickettsia prowazekii (typhus fever)
12. Salmonella species (salmonellosis)
13. Salmonella Typhi (typhoid fever)
14. Shigella (shigellosis)
15. Vibrio cholerae (cholera)
16. Yersinia pestis (plague)

Viruses

1. alphaviruses [e.g., Venezuelan equine encephalitis, eastern equine encephalitis, western equine encephalitis]
2. Arenaviruses
3. Ebola virus hemorrhagic fever
4. Lassa fever
5. Marburg virus hemorrhagic fever
6. Variola major (smallpox)

Toxins

1. Clostridium perfringens (Epsilon toxin)
2. Ricin toxin from Ricinus communis (castor beans)
3. Staphylococcal enterotoxin B

Emerging infectious diseases

1. Nipah virus
2. Hantavirus

Protozoa

1. Cryptosporidium parvum

Resources

View videos online

http://www.emedicine.com/med/topic2326.htm

http://www.hpa.org.uk/