Plasma plague
From Star Trek : Freedom's Wiki
A group of deadly virus types. An unclassified but extremely virulent strain of plasma plague threatened the densely populated Rachelis system in 2365. Significant research into plasma plague was conducted by Dr. Susan Nuress in 2295 in response to a similar outbreak on the planet Obi VI. One mutated strain developed during Nuress's research was found to grow more rapidly when exposed to eichner radiation.