Suddenly, the threat of bioterrorism on American soil doesn&#039t seem so far-fetched anymore.A series of anthrax hoaxes nearly shut down Canada&#039s immigration department this week. At the same time, a blue-ribbon US commission reported that an attack using nuclear, chemical, or biological agents was likely in the United States in the next 25 years. In Cambridge, a biopharmaceutical company races toward developing a new smallpox vaccine – in case a terrorist releases the deadly virus. Full Story