The Vastalimi gambit (Ace mass-market ed.)

At the close of the twenty-fourth century, a series of revolutions has caused the galaxy to descend into chaos. With the Galactic Union Army stretched thin, mercenary units have arisen for those who have the need-and the means-to hire them…
 
Kay, the alien member of the Cutter Force Initiative, has returned to her brutal home world of Vast on a mission of mercy. Before she joined the merc team, she was a great healer. And now her skills are sorely needed. Hundreds of Vastalimi-including her blood-kin-are dying mysteriously.
 
But is the plague a work of nature? Or is it a bioengineered virus, purposefully unleashed? Kay and Doc Wink will have to find out the hard way.
 
With the Cutter Force light-years away, the two find the odds against them-and on a planet like Vast, where violence abounds and life is cheap, they may be facing a foe they can't defeat…