title: Letter: Oral ulceration and infective agents.
mesh_terms: D003168:Complement Fixation Tests; D005892:Gingivitis, Necrotizing Ulcerative / Q000453:epidemiology*; D006801:Humans; D012606:Scotland; D018139:Simplexvirus / Q000302:isolation & purification; D013281:Stomatitis, Aphthous / Q000453:epidemiology*