title: Natural defense by saliva and mucosa against oral infection by Leptospira.
abstract: Leptospirosis caused by drinking water has not been as frequently reported as percutaneous infection. Resistance to oral infection by pathogenic Leptospira was examined in an experimental hamster infection model. The results suggested some natural defenses against oral infection by Leptospira. First, we found that characteristic linear agglutination of Leptospira rapidly occurs when mixed with human saliva. That human saliva attenuated the infectivity of the treated leptospires by its agglutination activity suggested saliva to be the first line of defense against oral infection by leptospires. Second, only 10(1) Leptospira organisms caused death after submucosal injection into oral mucosa in hamsters, but oral infection with drinking water containing 10(5) organisms/mL did not cause death. This result showed that the mucosa plays the role of a physical barrier. Third, hamsters intragastrically infected by leptospires, with doses lethal to hamsters in oral infection, showed no signs of illness, which suggested that gastric acid plays an important role in preventing oral infection. Based on these results, saliva, mucosa, and gastric acid make up a natural defense, which confers high resistance to hosts against oral infection by leptospires.
authors.affiliation: a Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
authors.forename: Tatsuma
authors.initials: T
authors.lastname: Asoh
authors.forename: Mitsumasa
authors.initials: M
authors.lastname: Saito
authors.forename: Sharon Y A M
authors.initials: SY
authors.lastname: Villanueva
authors.forename: Takaaki
authors.initials: T
authors.lastname: Kanemaru
authors.forename: Nina
authors.initials: N
authors.lastname: Gloriani
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Yoshida
mesh_terms: D000371:Agglutination / Q000187:drug effects / Q000276:immunology; D000818:Animals; D006224:Cricetinae; D005744:Gastric Acid / Q000502:physiology; D006026:Glycoside Hydrolases / Q000378:metabolism; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007921:Leptospira interrogans / Q000276:immunology*; D007922:Leptospirosis / Q000276:immunology*; D008297:Male; D008647:Mesocricetus; D008934:Mitogens / Q000494:pharmacology; D009061:Mouth Mucosa / Q000276:immunology*; D010504:Periodic Acid / Q000494:pharmacology; D012463:Saliva / Q000276:immunology*
chemical_list: D008934:Mitogens; D010504:Periodic Acid; C009288:metaperiodate; D006026:Glycoside Hydrolases
keywords: Leptospira; acide gastrique; and gastric acid; infection orale; mucosa; muqueuse; oral infection; saliva; salive