PlagueYersinia pestisSiphonapteraPlague VaccineMadagascarYersinia pseudotuberculosisVirulencePore Forming Cytotoxic ProteinsVirulence FactorsBacterial ProteinsBacterial Outer Membrane ProteinsAntigens, BacterialLymph NodesHistory, MedievalDisease ReservoirsRodentiaHistory, 17th CenturyRodent DiseasesHistory, 15th Century