Christopher W. Olsen, DVM, PhD
Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, USA
The intentional dispersal of Bacillus anthracis spores in 2001 brought bioterrorism to the forefront of the American psyche and raised significant concerns among the general public for the risks of biologic attacks directed at our human population. As veterinarians, we recognize that bioterrorism can also be aimed at animal populations (agri-bioterrorism), be they domestic, free-ranging, or exotic.
The intent of an agri-bioterrorist remains fundamentally to impact our human population. In the case of domestic animals, the specific objectives might be to decrease the overall food supply of a nation, to create skepticism in the safety of the food supply and thereby incite anger at the government, to disrupt international trade and national or multinational economies, or to indirectly cause human illness and death by employing zoonotic infectious agents. Despite the surveillance and control procedures in place in the United States, we remain a country that is vulnerable to an agri-bioterrorist attack, and the implications of such an attack could be staggering whether measured financially or in numbers of livestock lost.
Infection of free-ranging or exotic species via a bioterrorist attack has received much less attention than that directed toward domestic livestock. Infections in non-domestic animals could potentially result from either intentional targeting of these species or via spillover from a domestic animal epizootic. The objectives of targeting non-domestic species may be somewhat different from those of livestock, but the impact could still be very substantial: death of endangered species, loss of genetic/reproductive diversity, and the emotional impact of animal illness and death on zoo patrons.
A wide variety of pathogens have been considered as potential agri-bioterrorism agents. The CIA has highlighted 15 animal pathogens of greatest concern: African and classic swine fever viruses, avian influenza and Newcastle disease viruses, bluetongue virus, foot and mouth disease virus, goatpox and sheeppox viruses, pseudorabies virus, lyssaviruses, rinderpest and peste des petits ruminant viruses, porcine enteroviruses, and vesicular stomatitis virus. To this list we should probably add Bacillus anthracis (anthrax) and Burkholderia mallei (glanders). As is evident from this list, agri-bioterrorism can involve infectious agents that are specific for one animal species or for many species, agents associated with low to high case fatality rates, agents that require or do not require a vector for transmission, and agents that are or are not infectious for human beings as well as animals. After presenting the basic concepts of agri-bioterrorism, this seminar will review the clinical presentations in both domestic and exotic animal species of several of these agents.