WHICH DISEASE AGENTS ARE SUITABLE FOR BIOLOGICAL WARFARE?
Which disease? Bacteria, virus, or eukaryote? Most bacterial diseases can, in principle, be cured by antibiotics, whereas viral diseases cannot. On the other hand, bacteria are easier to grow than viruses. Many bacteria can be grown in relatively simple and cheap culture media. However, the production of virus particles requires culturing host cells for the virus to infectand consequently is more difficult because animal cells have complex growth requirements. Pathogenic eukaryotes such as Plasmodium (malaria) or Entamoeba (amoebic dysentery) have rarely even been considered as possible biowarfare agents because of the difficultyof culturing them on a large scale. Pathogenic fungi are a possible exception: some can be grown relatively easily. Although viruses might be grown in quantity by a government, large-scale virus culture is probably impractical for small groups of bioterrorists.
Outside the tropics, most incurable infectious diseases are due to viruses. The fundamental issue is that viruses are not themselves living cells but rely on the host cells they infect to assemble new virus particles. Consequently, chemical agents that prevent virus replication usually kill the host cells, too. A small and growing range of specific antiviral agents are available; nonetheless, no cure yet exists for most viral diseases.
Vaccination may protect against catching many viral diseases such as mumps, measles, and smallpox. However, protection against a viral biowarfare agent would require an effective vaccine against the particular strain of virus being used and vaccinating a sufficiently large proportion of the target population to prevent spread of the disease.
Among the bacterial diseases, anthrax, bubonic plague, brucellosis, tularemia, glanders, and melioidosis have all been suggested as possible biological weapons. The properties of these agents are summarized in Table 23.1 . A variety of viruses have been suggested, including both tropical diseases such as dengue and yellow fever and emerging diseases such as Lassa fever and Ebola virus, but the only consistent choice among viruses seems to be smallpox.