ドロレス顎口虫の寄生によるイノシシ胃壁の病変について-2-病理組織学的所見

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　ドロレス顎口虫の寄生するイノシシ胃壁15例について病理組織学的な検討を加え,以下の知見を得た.　1. 顎口虫の主たる寄生部位は胃底であるが,寄生域の粘膜下織には炎性反応が強く現われ,また寄生孔の周壁にはかなり著しい結合織増生が起きる.寄生孔壁の最内層(虫体と接する部分)は薄い壊死層,その外側は幼若結合織より成り,好酸球･組織球･リンパ球･プラスマ細胞が種々の割合でおびただしく浸潤,また血管の新生が著しい.更にその外側は部厚くて硬い結合織層に囲まれ,細胞浸潤は少なくなる.　2. 胃壁増厚部の粘膜下織には各種発育段階の虫体が穿入･埋在する.また虫体穿行跡の病変が所見される.そのうち肉眼上｢虫道巣｣と称したものは,組織破壊(または酵素による組織溶解)による軽出血,変性･壊死,好酸球集族を呈し,時には均質物も発現するが,このものを虫道性病巣と呼ぶ.他方,肉眼上｢微小巣｣と称したものの構造は,中心に均質物及び少量の壊死組織片･変性好酸球を容れ,周りに線維芽細胞がわずかに増殖し,類上皮細胞･異物巨細胞が発現,更にその外側を細胞浸潤を伴う薄い結合織層が取り囲み,病巣全体が小結節状を呈する.これを虫道性結節と呼ぶ. ところで虫道性結節は胃壁増厚を呈しない部位にも認められた.　3. 寄生域の筋層･漿膜においても,虫体の穿入像並びに虫道性病巣･虫道性結節を所見した.ただし,その頻度･程度は粘膜下織に比べるとかなり軽少である.なお筋層にこの種の病変を生じると,筋間結合織の増生(筋線維束の萎縮･消失)を来たし,好酸球を主とする細胞浸潤が著しい.漿膜でも肥厚と細胞浸潤を見る.　4. 噴門部･幽門部においても,虫体の穿入･寄生像と虫道性病巣･虫道性結節を所見した.病変の発現頻度や程度は胃底に比べるとはるかに軽少であるが, ドロレス顎口虫による病変が胃底に限定するものでないことを確認した点に意義がある.Histopathological examination was carried out on the stomachs of 15 wild boars infected with Gnathostoma doloresi. The results obtained are summarized as follows. 1. The fundus was a main locality of infection with G. doloresi. Inflammatory changes appeared distinctly in the tunica submucosa of such area of the gastric wall as infected with this parasite. Connective tissue proliferated remarkably around parasitic holes. The innermost layer (which got in contact with the worm body) of the parasitic hole was thin and necrotic. Its outer layer consisted of juvenile connective tissue, exhibiting a serious infiltration with large and small round cells and eosinophils and containing many blood vessels newly developed. Outside of this layer there was a surrounding thick layer of hard connective tissue, which was infiltrated a little less seriously with those cells than the preceding layer. Besides, the tunica submucosa presented changes caused by the penetration by immature and young adult worms. 2. In the tunica submucosa of such area of the gastric wall as infected with the parasite, foci were formed by the penetration and migration of immature and young adult worms. Foci produced by juvenile and young adult worms were relatively large and irregular in shape. They showed hemorrhage, necrosis, and congregation of eosinophils accompanying the destruction of tissues. A homogeneous structureless substance stained slightly with eosin appeared in some foci (which were called migratory-route foci). On the other hand, foci produced by larvae and immature worms were small and well defined. At the center of each of these foci were contained a homogeneous structureless substance and a few debris of necrotic tissue. Around them were infiltrating cells, such as eosinophils, large and small round cells, epithelioid cells, and giant cells against foreign body. The proportions among these cells were variable. The outermost layer of each focus was a thin connective tissue layer. In this manner nodular foci (called micro-foci) were formed. Besides, micro-foci were also seen in such part of the tunica submucosa as presenting no thickening. 3. In not a few cases, migratory-route foci and micro-foci produced by the penetration and migration of worms were found in the tunica muscularis, and serosa in the area of the gastric wall infected with the parasite. These changes were accompanied with hyperplasia of intermuscular connective tissue and diffuse infiltration with eosinophils. 4. In some cases worms having penetrated to stay and changes induced by the penetration and migration of worms were noticed even in the cardiac and pyloric regions of the stomach. Basically, these changes were histopathologically the same as those observed in the fundus of the organ.
宮崎大学農学部の論文

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芦沢広三
宮崎大学農学部家畜病理学教室

ドロレス顎口虫の寄生によるイノシシ胃壁の病変について-2-病理組織学的所見

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