Affiliation: | Laboratory of Experimental Animal Science, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori 034, Japan;Department of Animal Hygiene, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori 034, Japan;Department of Bacteriology, School of Medicine, Hirosaki University, Hirosaki 036, Japan |