Double Helix: Vectors — Dean Wesley Smith; Kristine Kathryn Rusch

Like a strand of mutating DNA, a deadly conspiracy winds its way through the entire Alpha Quadrant, just as it stretches across several years of Starfleet history--even to the Cardassian space station that will someday be known as Deep Space Nine''.

A virulent plague has striken Terok Nor, striking down both the enslaved Bajorans and their Cardassian oppressors, who blame each other for the growing epidemic. Dr. Katherine Pulaski, late of the Starship Enterpriser'", must work with the tyrannical Gul Dukat, as well as a rebel spy named Kira Nerys, to discover the true source of the infection that threatens them all!