"Double or Nothing"
  STAR TREK: The Next Generation #55

written by Peter David.
Published in August 1999 by Pocket Books.
ISBN: 0-671-03478-2, 277 pages

Synopsis:
  Like a lethal bacillus coursing through the bloodstream of the galaxy, a fiendish master plan has spread death and terror across the 24th century ‹ until two heroic captains risk everything to stamp out the evil at its source!
  For more than a decade, since the very beginning of the Starship Enterprise's mission, unknown enemies have unleashed a string of deadly biological weapons throughout the Alpha Quadrant, inflicting ghastly epidemics upon the Romulans, the Cardassians, the bajorans, and even the Federation.
  Now, at long last, Captain Jean-Luc Picard joins forces with Captain Mackenzie Calhoun of the Starship Excalibur to track down and confront the hidden architects of the plagues ‹ and avenge the deaths of thousands!