Bacterial Zoonotic Pathogens as Bioterroristic Agents

Abstract

Bioterrorism means the deliberate release of viruses, bacteria or other agents used to cause illness or death in people, animals or plants. Infectious agents or their toxins, often known for long as the cause of classical infectious diseases may be used for bioterroristic purposes, but not all of them are equally suited as biological weapons.

Anthrax, caused by Bacillus (B.) anthracis, a gram-positive spore-forming rod, is a very long known animal disease with zoonotic potential. The ability to form endospores makes B. anthracis especially suitable for bioterroristic use as these endospores are highly resistant to environmental influences, disinfectants, heat or radiation and can easily be aerosolized. B. anthracis possesses two main virulence factors, the anthrax toxin and the ability to form a capsule. Both virulence factors are plasmid-encoded. Human anthrax manifests itself as cutaneous anthrax, alimentary anthrax, inhalational anthrax or injectional anthrax.

Tularemia is a zoonosis with a broad host range. Wildlife animals are the main reservoir for humans. It is especially a disease of hares, rabbits and other rodents. As humans are highly susceptible for tularemia, its agent, Francisella (F.) tularensis, which can be transmitted by aerosol, is supposed to have a bioterroristic potential, although no attempts of bioterroristic misuse have been known so far. While the most virulent subspecies F. tularensis ssp. tularensis is confined to North America, a less virulent subspecies, F. tularensis ssp. holarctica, is widely distributed over the Northern hemisphere, predominantly over North America, Scandinavia, Russia and Japan. Human tularemia is a febrile, inflammatory disease, which starts with unspecific symptoms like headache, growing pains, fever, chills and weakness. The further course of disease depends on the agent’s virulence and its route of entry.