Why is biophysicist Steven Block so concerned about smallpox?
After all, more than 20 years have passed since the World Health Organization (WHO) announced the eradication of this highly contagious and incurable disease.
``Simply put, smallpox represents a direct threat to the entire world,`` says Block, a professor of biological sciences and applied physics at Stanford.
He points out that, although the disease has been eliminated in the wild, frozen stocks of smallpox virus are still maintained by the governments of the United States and Russia.
If rogue politicians or terrorists were to get hold of the remaining supplies, ``the consequences could be disastrous,`` he warns.
But Block is haunted by more than the threat of a smallpox attack.
He points to some two dozen conventional biological agents - including anthrax, Ebola and typhus - plus an unknown number of genetically engineered organisms that terrorists could unleash on an unsuspecting public.
``We`re tempted to say that nobody in their right mind would ever use these things,`` he says, ``but not everybody is in their right mind!``
Block paints a disturbing picture of the international bioterrorist threat in an article published in the Jan./Feb. issue of American Scientist magazine.
His expertise in biological warfare stems from his work with JASON, an organization of primarily academic scientists who dedicate a portion of their time to solving national security problems. Members of JASON often serve as consultants to the Defense Department and other U.S. agencies
``In my opinion,`` he writes, ``the terrorist threat is very real, and it`s about to get worse.``
Block argues that the United States and other developed countries should be doing more to prevent the spread of biological weaponry, which he calls ``a serious threat to peace in the twenty-first century.``