Pathological study on enteric Helicobacter infection in captive cheetahs (Acinonyx jubatus) in Japan.

チーターを始めとする大型肉食ネコ科動物における腸型ヘリコバクターに関する報告は見当たらない。そこで,チーターにおける腸型ヘリコバクターの感染状況と病変との関連を明らかにすることを目的として,本研究を行った。1994年から2002年の間に病性鑑定を行った63頭より今回の検索に適した36頭を選択し,これらの消化管(十二指腸7例[DD],小腸28例[SI],盲腸15例[CC],結腸37例[LI])を検索した。また全ての症例および部位に程度に差があったが,リンパ・プラズマ細胞性腸炎が観察され,特に盲腸で高度であった。糜爛・潰瘍が[DD]1(14%),[SI]2(7%),[CC]10(63%)[LI]12(40%)でみられ,粘膜固有層へのアミロイド沈着が[DD]5(71%),[SI]28(97%),[CC]11(69%)[LI]23(77%)に認められた。ヘリコバクターは,陰窩の拡張を伴って腺底部の腺腔内を中心に21(57%)に観察され,その内訳は[DD]0,[SI]6(21%),[CC]9(56%)[LI]14(47%)であった。ヘリコバクターは直線的で,約3.5×0.3μmで,規則的に密に巻き付く細胞周囲線維を有していた.以上の結果から,H.billsあるいはFlexispira rappiniと考えられるヘリコバクターがチーターに高率に感染していることが明らかになった。ヘリコバクター感染と病変との関連は一見ないようであった。しかしながら,ヘリコバクター感染がリンパ・プラズマ細胞性腸炎や糜爛・潰瘍とどのように関連するか,さらに検討する必要がある。また,調査可能であったチーター全てに認められた消化器症状の発現には,腸炎ないしはアミロイド沈着が重要な役割を担っていることがわかった。特にアミロイド沈着は高度で,他の臓器への沈着とともにチーターの死因として重要な病変と考えた。There has been no report on the prevalence and pathogenicity of enteric Helicobacter in large felid including cheetahs. The pathogenicity of most eneric Helicobacters remains still unknown. Pathological examination of 63 captive cheetahs revealed a high incidence of lymphocytic enteritis. We therefore studied the prevalence of enteric Helicobacter infection and its pathogenicity in captive cheetahs, in an attempt to identify the cause of this desease. Pathological studies were carried out on 87 interstinal samples from 36 cheetahs that died in captivity (7 duodenun, 28 jejunoileum, 17 colon, 15 cecum, 20 rectum). Immunostain identified enteric Helicobacter in 21 cheetahs out of examined 36 csaes (58%). The site prevalence was 0 duodenum, 6 jejunoileum (21%), 9 cecum (60%), 9 colon (53%) and 8 rectum (40%), Helicobacter spp. Were mostly present in the crypts, either scattering or clumping, and patterns by SEM, they were straight and rodlike in shape and 3～3.5×0.3 microns in size, with regular, densely aligned pericytoplasmic fibers. Intestinal lesions included lymphocytic enteritis, thickened lamina propria, dilatated crypts, amyloid deposition, and erosion and ulceration. In all animals examined, varying lymphocytic enteritis was present at least, in the part of the intestines, and was more prominent in the cecum. Advanced amyloid deposition was also highly prevalent, appearing in 27/28 samples of small intersting (96%) and 38/52 samples of the large intesting (73%). While gastric Helicobacter infection is well known in cheetahs, our results also indicated a high rate (58%) if enteric Helicobacter infection among them. Ultrastructural observation suggested that the bacteria might be H. bilis or Flexispira rappini. Lympho-plasma cytic enteritis and intestinal amyloidosis were also highly prevalent in the animals observed. It seems that there were no relation to Helicobacter infection and the pathological changes. However, will have to consider how helicobacter infection relates to the lesions and ulcer further. Our results therefore suggest that amyloid deposition in the intestines as well as amyloidosis in other organs, will be a major life-threatenining factor in captive cheetahs. (Presented at 52nd ACVP Meeting).P(論文)特集application/pdfFEATURE ARTICLESdepartmental bulletin pape