title: Molecular genotyping of anisakis larvae in Middle Eastern Japan and endoscopic evidence for preferential penetration of normal over atrophic mucosa.
abstract: BACKGROUND
  Anisakiasis is a parasitic disease caused primarily by Anisakis spp. larvae in Asia and in Western countries. The aim of this study was to investigate the genotype of Anisakis larvae endoscopically removed from Middle Eastern Japanese patients and to determine whether mucosal atrophy affects the risk of penetration in gastric anisakiasis.
  
  
  METHODS
  In this study, 57 larvae collected from 44 patients with anisakiasis (42 gastric and 2 colonic anisakiasis) were analyzed retrospectively. Genotyping was confirmed by restriction fragment length polymorphism (RFLP) analysis of ITS regions and by sequencing the mitochondrial small subunit (SSU) region. In the cases of gastric anisakiasis, correlation analyses were conducted between the frequency of larval penetration in normal/atrophic area and the manifestation of clinical symptoms.
  
  
  RESULTS
  Nearly all larvae were A. simplex seusu stricto (s.s.) (99%), and one larva displayed a hybrid genotype. The A. simplex larvae penetrated normal mucosa more frequently than atrophic area (p = 0.005). Finally, patients with normal mucosa infection were more likely to exhibit clinical symptoms than those with atrophic mucosa infection (odds ratio, 6.96; 95% confidence interval, 1.52-31.8).
  
  
  CONCLUSIONS
  In Japan, A. simplex s.s. is the main etiological agent of human anisakiasis and tends to penetrate normal gastric mucosa. Careful endoscopic examination of normal gastric mucosa, particularly in the greater curvature of the stomach will improve the detection of Anisakis larvae.
authors.affiliation: Department of Environmental Parasitology, Graduate School of Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan ; Department of Gastroenterology, Toukatsu Hospital, Nagareyama-shi, Chiba, Japan.
authors.forename: Toshio
authors.initials: T
authors.lastname: Arai
authors.affiliation: Department of Environmental Parasitology, Graduate School of Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Akao
authors.affiliation: Department of Environmental Parasitology, Graduate School of Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan.
authors.forename: Takenori
authors.initials: T
authors.lastname: Seki
authors.affiliation: Department of Environmental Parasitology, Graduate School of Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kumagai
authors.affiliation: Department of Environmental Parasitology, Graduate School of Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Ishikawa
authors.affiliation: Department of Environmental Parasitology, Graduate School of Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Ohta
authors.affiliation: Department of Gastroenterology, Kameda Medical Center, Kamogawa, Chiba, Japan.
authors.forename: Nobuto
authors.initials: N
authors.lastname: Hirata
authors.affiliation: Department of Gastroenterology, Kameda Medical Center, Kamogawa, Chiba, Japan.
authors.forename: So
authors.initials: S
authors.lastname: Nakaji
authors.affiliation: Department of Gastroenterology, Kameda Medical Center, Kamogawa, Chiba, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamauchi
authors.affiliation: Department of Gastroenterology, Kameda Medical Center, Kamogawa, Chiba, Japan.
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Hirai
authors.affiliation: Department of Gastroenterology, Kameda Medical Center, Kamogawa, Chiba, Japan.
authors.forename: Toshiyasu
authors.initials: T
authors.lastname: Shiratori
authors.affiliation: Department of Gastroenterology, Kameda Medical Center, Kamogawa, Chiba, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: Department of Gastroenterology, Kameda Medical Center, Kamogawa, Chiba, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fujii
authors.affiliation: Department of Gastroenterology, Kameda Medical Center, Kamogawa, Chiba, Japan.
authors.forename: Eiji
authors.initials: E
authors.lastname: Ishii
authors.affiliation: Department of Endoscopy, Kameda Medical Center, Kamogawa, Chiba, Japan.
authors.forename: Mikio
authors.initials: M
authors.lastname: Naito
authors.affiliation: Department of Endoscopy, Kameda Medical Center, Kamogawa, Chiba, Japan.
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Saitoh
authors.affiliation: Department of Gastroenterology, Toukatsu Hospital, Nagareyama-shi, Chiba, Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Yamaguchi
authors.affiliation: Department of Pathology, Toukatsu Hospital, Nagareyama-shi, Chiba, Japan.
authors.forename: Nobumitsu
authors.initials: N
authors.lastname: Shibata
authors.affiliation: Department of Pathology, Toukatsu Hospital, Nagareyama-shi, Chiba, Japan.
authors.forename: Masamune
authors.initials: M
authors.lastname: Shimo
authors.affiliation: Laboratory of Veterinary Pathology, Azabu University, Sagamihara, Kanagawa, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Tokiwa
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D017129:Anisakiasis / Q000469:parasitology* / Q000473:pathology*; D017163:Anisakis / Q000235:genetics / Q000472:pathogenicity*; D001284:Atrophy / Q000469:parasitology; D005260:Female; D005753:Gastric Mucosa / Q000469:parasitology / Q000473:pathology*; D005838:Genotype; D006801:Humans; D007564:Japan; D007814:Larva / Q000235:genetics / Q000472:pathogenicity*; D008297:Male; D008875:Middle Aged