KOLTSOVO, RUSSIA-- Smallpox, humankind9s greatest scourge, was banished from the wild decades ago. New fears that bioterrorists may try to resurrect the virus have thrown two controversial research programs--at the two places on Earth where it is permitted to keep live smallpox virus, one in the United States and one in Russia--into high gear. The researchers are in a hurry, because although the executive board of the World Health Organization recommended in January giving smallpox--which had been slated for destruction several times before--another stay of execution to allow researchers more time to study it, pressure is mounting to get rid of it once and for all (see sidebar).