Most scientists studying the Exsurgence virus think they can discern a definite purpose for most strains, which typically amounts to "creating minions or sleeper agents" in enough different ways that the opposition is kept on their toes. The Bootstrap strain, however, has attracted more wild guesses as to its purpose than any since Watts-MacLeod.
This strain is unique in that it doesn't affect transhumans, uplifts, or AGIs, but rather non-sapient animals, either unmodified or "smart" variants. Already sapient beings can carry the virus, but it doesn't seem to affect them at all, though most cases have also been infected by another strain.
The first recorded occurrence of the Boostrap virus was carried by an Exsurgent zookeeper working in a wealthy hypercorp executive's private menagerie habitat. He infected several of the animals before Firewall intervened, most of the information on the virus comes from the records of the other zookeepers and observations made by the Sentinel team that investigated. The zoo habitat was nuked after the Sentinels submitted their report.
Some hypothesize that the Bootstrap strain is intended simply to sow chaos in wild areas or habitats dependent on smart animals. Others think it's supposed to produce a new set of infectees following the extinction of the primary sophont species. Some conspiracy theorists even believe that it was developed by one of the scientists at Fortean to accelerate uplift of new species.
Timeframe: Infection to 5 hours.
Stress: SV 1d10-2 per hour.
Infected animals display erratic and highly aggressive behavior during this phase. Screeching, gnawing at bindings, biting every living thing in sight, the lattermost behavior also tends to spread the virus.
Timeframe: End of Stage 1 to six months.
Stress: SV 1d10 per month.
During this stage of infection animals tend to become timid and reclusive. Their brains begin to form quantum entanglements and fields similar to those in asyncs, causing them to gain +1 COG every month. The changes in the subject's brain are extremely stressful, by the end of the stage the animal gains at least one mental disorder, regardless of the amount of stress and traumas sustained.
Timeframe: six to twelve months.
Stress: SV 1d10-2 per month.
The massively accelerated mockery of uplift complete, the victim's body restructures itself so that it can more effectively function as a sapient being. Bones in the forepaws and hips gradually warp into hands and a humanoid "bowl" pelvis for bipedalism, and the larynx becomes much more complex to the point where "bootstrapped" animals can learn to speak transhuman languages. They can also be infected by other strains of the Exsurgence virus at this point, suffering a -20 penalty to resist infection similar to asyncs. There have also been numerous reports of animals at this stage and later displaying psi-sleights, though it remains unverified whether the Bootstrap strain or subsequent infection by Watts-MacLeod was responsible.