Quarantine

Both Sleeper and Talocan sites make reference to a large effort to quarantine objects. The logical conclusion is that both races were attacked by a highly deadly virus.

The Talocan show no signs of an infomorph society. Therefore there were either two really deadly viruses in the same area of space, or the Mirror's medical enclave refers to treating biological people.

A digital virus doesn't create itself, therefore such a virus would have to be manufactured. Furthermore, an infected piece of hardware wouldn't be stored in a medical facility where they deal with triage etc, where as that's the logical place for 'bio-ware' to go when it is damaged.

From this I'd conclude that there was one virus, and that it was biological in nature.