Agents

Persistence in the transmission environment Level 1: Years Level 2: 8-24 hours Level 3: <1 hour

Bioterrorism dissemination

Infective Dose

Inhalation Anthrax

Level 1: Very persistent

-Postal package - air dispersal and transmission - no person to person transmission

8,000-50,000 spores

Plague Yersinia pestis

Level 3: not persistent

-Airborne (aerosol attacks), - 2nd transmission close contact (droplet borne)

100 – 500 organisms

Smallpox

Level 3: not persistent

Airborne (aerosol attacks), close contact (droplet borne, fomites) dissemination of contaminated bedding and clothing

Assumed low (10-100 organisms)

Tularaemia

Level 1: Very persistent

airborne inhalation

10-50 organisms

Viral hemorrhagic fevers

Level 2; Persistent

Surfaces, food

1 – 10 organisms

Brucellosis

Level 2; persistent

Surfaces, Aerosols, Food

10-100 organisms

Q-fever Coxiellaburnetii

Level 1; Very persistent

Air, surfaces

1 – 10 organisms

Ricin toxin

Level 1; very persistent

Air, food, or water.

3-5 mg/kg, LD50 in mice

Table 1: Persistence, dissemination, and infectious dose of bioagents. [29]