PlagueYersinia pestisPlague VaccineSiphonapteraMadagascarYersinia pseudotuberculosisPore Forming Cytotoxic ProteinsVirulenceVirulence FactorsBacterial ProteinsBacterial Outer Membrane ProteinsAntigens, BacterialLymph NodesHistory, MedievalRodentiaDisease ReservoirsRodent DiseasesHistory, 17th Century