The Changeling Plague — Syne Mitchell

The Beijing Treaty of 2013, passed unanimously by the nations of the civilized world, prohibits viral engineering, believed responsible for planetary plagues that decimated the human population. Geneticists nevertheless continue to engage in illegal experimentation with DNA....

Geoffrey Allen is a millionaire able to buy almost everything his heart desires. But the one thing he hasn't been able to buy is a cure for the cystic fibrosis that is slowly killing him. The disease destroying his lungs is immune to every known--and legal--medical cure. Now, desperate and scared, with nothing left to lose, Geoffrey becomes a human guinea pig, injecting himself with an untried viral treatment designed to reprogram his DNA.

Seemingly cured, Geoffrey is the picture of perfect health. But those in contact with him begin to suffer from extraordinary diseases and deformities that are hereditary in nature--even though they have no history of such ailments in their families.

The virus Geoffrey carries is rewriting the DNA of everyone he encounters.

And it's spreading....