Star Trek the Next Generation: Double-Helix (Book 2) - Vectors

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 Enterprise, 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!