Recognition of the rapid response (hours or days) in immunomodulatory factors such as cytokines in the blood to various pathogens suggests that microorganism-specific cytokine tests may permit more rapid monitoring of host-specific responses. An example is the adoption of assays to monitor for mycobacteria-specific antigen-induced secretion of the cytokine interferon-gamma in blood mononuclear cells as a more rapid diagnostic assay than slower cultivation protocols (weeks) required for isolation of Mycobacterium bovis from cattle (Stabel, 1996). Such tests could also provide rapid data on new immunosuppressive pathogens, naturally occurring or bioengineered, by revealing significant decreases in certain cytokine levels. Another example is the recognition that some immunomodulatory factors (the cytokine IL-4) coexpressed with a virus may increase the virulence of certain viruses (mousepox) in the host (Jackson et al., 2001). Monitoring of a dramatically up-regulated single cytokine level could signal the presence of such a bioengineered pathogen-cytokine recombinant or guide treatment with antibodies to the relevant cytokine or counter-regulatory cytokines. Besides of diagnostic value, innate immune factors (such as cytokines and interferons) occurring early (hours or first days) after infection, and preceding the acquired immune responses, might be manipulated as treatment modalities to reduce or prevent infection of contact or susceptible animals. Early innate immunomodulator intervention strategies might block or reduce pathogen infection and shedding, decreasing transmission to other animals or making contact animals more resistant to infection.

INTENTIONALLY INTRODUCED PATHOGENS AND DISEASES OF TOXICOLOGICAL ORIGIN

Of course, an act of bioterrorism need not involve a bioengineered pathogen. The intentional spread of known microorganisms or microbial toxins can be accomplished using the same routes as accidental introductions, which occur when disease agents are brought to new areas via the movement of air and water, fomites, vectors, infected animals, or animal products.

Currently, if naturally occurring, endemic agents were intentionally introduced into a new locale, investigatory agencies would be reliant solely on the pattern of outbreak to distinguish an attack, since there is currently no methodology to distinguish between intentionally versus accidentally introduced. The purposeful introduction of an exotic disease through channels of international commerce could also be disguised, since such an occurrence could as easily be the result of an accident as not. In the 2003 National Research Council report Countering Agricultural Bioterrorism, the Committee on Biological Threats to Agricultural Plants



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