ニホンウナギの Edwardsiella tarda 感染症の病理組織学的研究-Ⅱ. : 自然感染-化膿性肝炎型
1) 養殖ニホンウナギの Edwardsiella tarda 感染症のもう一つの発現型である化膿性肝炎型について細述した。2) 病理組織学的検討の結果, 肝臓での発病は類洞内に細菌を呑食した細胞が現われることに始まり, その類洞を中心に微小感染病巣から膿瘍病巣が発展していた。膿瘍病巣の軟化融解により病巣の拡大が起り, 敗血病巣, 潰瘍病巣へと進行していた。3) 全身感染の段階で, 心臓, 鯉, 体側筋組織に転移病巣が現われ, 脾臓は細胞増生浸潤性反応を, 腎臓の造血組織は造血細胞の過形成を示していた。4) 以上の病理組織学的所見から, 肝臓の感染病巣の炎症反応は化膿性炎で特徴づけられた。また血管間葉性組織の反応は発現型によって相違していた。
Histopathological studies were made on 9 diseased eels with suppurative hepatitis caused by Edwardsiella tarda infection. Fish in advanced stages of the disease showed a reddening of fins and the body surface and a swelling of the liver region of the trunk. Anatomically abscesses were observed in the liver, some of which were followed by the ulcer formation.The primary, detectable histopathological change in the liver was the appearance of micro abscesses containing macrophages phagocytizing bacteria in the sinusoids. As the disease progressed enlarged abscesses which were composed of a large number of juvenile neutrophils and necrotized hepatic cells and were thought to develop from the above‐mentioned primary foci became more noticeable. Extensive lesions accompanied by liquefaction of abscesses and bacterial multiplication were found to involve large blood‐vessels and in such cases metastatic necrotic lesions were observed in various parts of the liver and the hepatic cells were in an intensive fatty degeneration. While healing lesions demarcated by precipitated flbrin and newly formed granulation tissues were often observed. Peripheral extensive lesions often developed into ulcers and suppurative lesions were found in the region of the body musculature adjacent to large ulcers of the liver. In the stage of the generalized infection metastatic lesions were observed in the heart, gills and body musculature, and the spleen and the hematopoietic tissue of the kidney showed a cellular proliferative‐infiltrative reaction, and a marked hyperplastic reaction of the hematopoietic cells, respectively.
魚病研究 11 (2), 67-75, 1976-09-01