Retroviruses and other latent viruses: the deadliest of pathogens are not necessarily the best candidates for bioterrorism.

Field: Medicine (Health Sciences)

HIV-1 (and other viral causes of latent, chronic infections) is not a likely candidate for bioterrorism. Scenarios resulting in the introduction of retroviral infections into a large population generally seem impractical and unpredictable as bioterrorist plots, especially relative to the frightening simplicity of deadly anthrax spores or smallpox virions. As evidenced in the above discussion, contaminating the blood supply would require a highly sophisticated plan resulting in effects of rather limited ultimate scope, and would have to evade an extremely effective screening process already in full force. Contaminating other agents given parenterally is also a potential concern, but again the virus has rather fastidious growth characteristics outside of the human host, and even if this could be accomplished it would presumably affect only a very limited number of targeted individuals. Finally, the idea of a kind of"sexual suicide bomber", an individual deliberately introduced into the community to spread a deadly infectious disease might be proposed. However, as discussed in this commentary, the impact of this rather implausible scenario would be substantially delayed, unreliable, and ultimately could be controlled through a heightened response of already existing public health mechanisms. Whereas HIV has resulted in the "perfect storm" of a devastating pandemic, a major cause of worldwide morbidity and mortality that is tremendously challenging to control, it does not match up very effectively with the Centers for Disease Control and Prevention (CDC) Category A definition of an ideal agent of bioterrorism. It is not easily spread through casual or incidental contact and does not cause a substantial immediate death toll. Instead it is spread only through sexual, parenteral, or maternal/fetal transmission, and generally requires a prolonged and variable clinical latency period prior to disease progression and death. The U.S. public health system is already reasonably well equipped to screen, test, and treat HIV infection (although there is undeniably a greater need for community outreach and education). New introduction of HIV infections in the community via a bioterrorism plot might result in a quantitative difference-but not a funda-mental shift in CDC testing and monitoring plans. Thus, HIV does not match up very effectively as a category B agent of bioterrorism. A growing number of antiviral drugs, increasingly tolerable and conveniently dosed, are making the concept of post-exposure (and even pre-exposure) prophylactic HIV therapy a feasible consideration in many circumstances. The high mutability and adaptability of HIV is a key to its success as a chronic, latent pathogen. These characteristics make vaccine and antiviral drug development an ever-present challenge. On the other hand, there are no data to suggest this complex virus could be eas-ily modified so that it would be more easily transmissible or more rapidly, predictably fatal; therefore, making it an unlikely category C agent as well. Indeed, research during the past decade suggests that HIV disease progression is largely dependent on a complex, individualized host/pathogen interaction rather than the presence of a universal viral trait or toxin. The very characteristics that make a universal vaccine or curative treatment for HIV/AIDS so difficult to achieve also make it a rather poor candidate to be predictably manipulated and wielded as a bioterrorist's weapon.