Zoonotic pathogens are twice as likely to be associated with newly discovered, emerging, human illnesses.  Of all the infectious agents that humans, approximately 60% are zoonotic.  The 1999 outbreak of West Nile virus in New York City was a perfect illustration of the challenges societies face in addressing zoonotic diseases.  There have been many other emerging zoonotic disease outbreaks, including the Nipah virus outbreak in Malaysia in 1998-1999, the severe acute respiratory syndrome (SARS) outbreak in 2003 and most recently, the avian influenza outbreak that is spreading throughout Asia, Europe and Africa.  Many of the agents of bioterrorism are zoonotic in origin.  In fact, five of the top six “category A” disease agents designated as potential bioterror threats by the United States Centers for Disease Control and Prevention (CDC) are zoonoses.  Reasons for the emergence of these zoonotic disease outbreaks are multiple human population pressures, intensive agricultural pressures, intensive agricultural practices, consumption of bush meat, importing and dumping of used tires that serve as reservoirs for mosquito breeding,  air travel and a global trade in exotic animals.  Since scientists have identified less than 1% of the viruses on the planet, it should be anticipated that many more zoonotic viral pathogens will emerge.