Nanovirus

A nanovirus, also known as a nanokiller or nanogene, was a selective virus designed to kill only an individual or specific groups of people that it had been developed to, without harming other undesired individuals.

Nanoviruses targeting specific beings or groups of beings were notoriously difficult to produce due to the need of identifying an entire genome, or else the virus would not attack the target. Routine natural mutation, interbreeding, and genetic engineering would make an individual immune to the virus's effects. This weakness could be skirted by having the virus target a specific, unchanging gene sequence that would make its target or targets stand out from the larger population such as the one used to increase the rate of aging within clone troopers. More dangerously, a nanovirus could be keyed less specifically in order to kill subjects of an entire race, such as humans, indiscriminately.

Text and facts from the “Nanovirus” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.