CtenocephalidesFlea InfestationsSiphonapteraRickettsia felisEctoparasitic InfestationsRickettsia InfectionsAntiparasitic AgentsNitro CompoundsDog DiseasesCat DiseasesRhipicephalus sanguineusMethoprenePhthirapteraTyphus, Endemic Flea-BorneRickettsia typhiCatsInsecticidesDogsRickettsiaPetsPositron-Emission Tomography