PULASKI: I am unfamiliar with this symbol. DATA: It indicates a genetically engineered biological life-form. PULASKI: About twenty percent of the specimens fall into that category. Some eager beaver at play. DATA: Query: "eager beaver?" PULASKI: Well in this case, eager beaver refers to some over achieving genetic engineer, who probably because of lack of anything better to do has forced this strain of virus to mutate, just so he can see how bad bad can get.
Source: wiktionary