The targeted organism must not have a non-human reservoir (or, in the case of animal diseases, the infection reservoir must be an easily identifiable species, as in the case of rinderpest), and/or amplify in the environment.
Ciljani organizam ne sme imati nehumani rezervoar (ili, u slučaju bolesti životinja, rezervoar za infekciju mora biti lako prepoznatljiva vrsta, kao u slučaju goveđe kuge), i/ili se pojačava u okolini.