A particular grouping of deadly virus types, this plague is an extremely virulent and unclassified strain of plasma which threatened the dense population of the Rachelis system in 2365. In 2295, Doctor Susan Nuress conducted significant research into plasma plague in response to a similar outbreak on planet Obi VI at that time. One mutated strain among these virus types which had been observed in the scope Nuress' research was discovered to develop much more rapidly when exposed to eichner radiation. A strain similar to this one endangered not merely the Rachelis system, but the U.S.S. Enterprise NCC-1701-D and her crew during their mission to transport specimens of plasma plague to Science Station Tango Sierra as part of the effort to combat the outbreak in the Rachelis system.