Viral Plaque AssaySkin Diseases, ViralCat DiseasesVirus ReplicationHemolytic Plaque TechniqueCell LinePlaque, AtheroscleroticDental PlaqueTreatment OutcomeVirus CultivationOutcome Assessment (Health Care)Antibody-Producing CellsCytopathogenic Effect, ViralRickettsia rickettsiiPregnancy OutcomeRickettsia prowazekiiTime FactorsRickettsiaPancreatinHaplorhiniCulture TechniquesIdoxuridineNeutral RedVirologyMethodsRetrospective StudiesVero CellsMethylcelluloseFollow-Up StudiesPokeweed MitogensRickettsia typhiAntiviral AgentsProspective StudiesCercopithecus aethiops