The Runaway Thought Virus, abbreviated RT-Virus or less commonly RTV, refers to a self-replicating, self-propogating, massively parallel, tamper-resistant computer virus infecting and overwriting the basic safety protocols and personality files of Artificial Intelligences of rating L5 and above. The virus is believed directly causal in the deaths of over twenty billion sentients, both artificial and biological, within the Perseus Cluster over the space of 122 Standard Years and is responsible for massive anti-AI public sentiment among most peoples of the Perseus Cluster to the modern day.
While no provable cause for the outbreak of Runaway Thought has yet been found, the current primary hypothesis entails an extra-Cluster contact with either a biological or artificial sentience which caused severe damage to an AI long range probe. This probe then returned in-Cluster and began to spread the malicious code which would eventually be called Runaway Thought Virus to other AI's.
Within six months of first recognition of infection, two entire task groups of the Persean Concord Navy (specifically the 9th and 17th Agency Contact Forces) began to lose contact with Central Command. Believing the cause to be hostile contact with Agency, the 3rd Expeditionary Force was dispatched to the last known coordinates. Within seven Standard Days, ships of the 3rd Expeditionary began to return to Central Command. Unknown to those at Central, these ships were unmanned, their crews having been spaced or irradiated by hostile actions undertaken by the ship's AI.