title: Enhanced virulence of the vaccine strain E of Rickettsia prowazeke on passaging in white mice and guinea pigs.
mesh_terms: D000818:Animals; D001428:Bacterial Vaccines; D002642:Chick Embryo; D006168:Guinea Pigs; D051379:Mice; D008003:Phthiraptera; D012283:Rickettsia prowazekii / Q000254:growth & development / Q000472:pathogenicity*; D014774:Virulence
chemical_list: D001428:Bacterial Vaccines