I nominate:
Berserker by Steven Jordan
THE FIRST VOYAGE—Carolyn Kestral, discharged Galarchy Ranger, begins her new life as a freighter captain and collects a small crew. But there is a question of whether the Berserker virus that forced her Ranger discharge is still capable of being activated and turning her into a deadly human weapon. If it is merely dormant, will it be set off by a clandestine first run and a dangerous run-in with the Spiders in deep space? Will her crew stick around long enough to find out?
Available DRM free for $2.50 at
http://www.stevejordanbooks.com/novels.htm#berserker