Morphogenic virus
From Star Trek : Freedom's Wiki
A virus engineered by Section 31 with the intent of killing the Founders who link with Odo. In 2372, The main symptom is a decreasing ability to shapeshift, accompanied by pain and peeling skin; the progress is accelerated by frequent shapeshifting and in the final stage of the disease, the Changeling cannot revert back to liquid state at all and die in a solid form. The cure for the disease contains a nucleotide marking sequence consisting of adanine, asporadine, lytastolanine, and radanine.