PlagueYersinia pestisSiphonapteraPlague VaccineMadagascarYersinia pseudotuberculosisVirulencePore Forming Cytotoxic ProteinsVirulence FactorsBacterial ProteinsBacterial Outer Membrane ProteinsAntigens, BacterialLymph NodesHistory, MedievalRodentiaDisease ReservoirsRodent DiseasesHistory, 17th CenturyHistory, 15th Century