1972〜73年わが国に多発した牛の流早死産および子牛のArthrogryposis-Hydranencephaly Syndromeに関する調査研究(第3報) : 異常子牛の病理学的所見
スポンサーリンク
概要
- 論文の詳細を見る
1972年夏から1973年春にかけて, 南九州に初発し関東以西の本邦各地に, 牛の流産, 早産,死産および四肢と脳の奇形を伴う異常子牛の出産が多発した. われわれは宮崎県内に発生した異常子牛48症例について,病理学的所見の観察と病原微生物の分離を試み,次のような結果を得た. 1. 供試異常子牛は肉用牛(黒毛和種)38例,乳用牛(ホルスタイン種)10例であり,性別は雄が26例,雌が22例で,1972年9月から1973年5月までに生まれたものである. 日齢は0～10日齢(死産胎児6例を含む)のもの27例,ll～30日齢のもの9例,31～60日齢のもの4例,61日齢以上のもの8例で,最高日齢は252日であった. 2. 供試異常子牛は,その病理学的形態から次の3型に分けられる.すなわち,起立不能で吸乳カの弱い虚弱子牛(3例), 四肢の屈伸不能を示す関節彎曲症(29例, うち6例は脳奇形を合併)および脳奇形(22例, うち6例は関節彎曲症を合併)である. 本病発生当初の1972年9月から12月までに出産した供試牛は虚弱子牛と関節彎曲症であり,1973年1月以降出産の症例に脳奇形が現われた. 3. 四肢の屈伸不能を示す関節彎曲症29例の内訳は, 四肢全部の異常が3例, 3肢の異常が2例,2肢の異常が16例(左右両前肢が9例,左右両後肢が6例,前後肢1肢ずつが1例),1肢のみの異常が8例.異常肢総計58肢のうち,屈曲して伸びないもの40肢, 伸展したまま屈折不能のものが18肢で屈位硬直が多かった. なお, 四肢の屈伸不能に加えて脊柱の彎曲を示したものが10例あった. 罹患肢の筋肉は発育不全で萎縮しているが,全般に骨や関節面に著変はなかった. 4. 脳奇形は22例で,そのうち四肢の関節彎曲症を併発しているものが6例あった. 脳の奇形程度は,大脳の両半球を全く欠如したHydro-anencephaliaが14例,主として大脳側頭葉が欠損しているHydro-micrencephaliaが8例であった. 5. 全般を通じて最も主要な病理組織学的変状は中枢神系に認められた. すなわち,大脳の欠如や欠損を起こしたものの残存脳組織も, 肉眼的には脳に変化のない関節彎曲症の脳組織も, ともに灰白質錐体細胞を主とする神経細胞の濃縮や空胞化を伴う変性,著明なノイロノファギー, グリア細胞の増殖,未分化神経細胞の遺残と思われる円形細胞の集簇巣が所見された. 本症の発生初期に出産した症例では血管周囲の出血や円形細胞の浸潤,小出血巣, 脊髄前角の脱髄など若干の炎症性反応と見られる所見を認めたが,全般的には変性を主体とした中枢神経系の変状であり,1959～60年に西日本一帯で発生した牛の類似疾患の病理像と酷似している. 6. 本症の病理発生は,胎児の時期に中枢神経系を侵害するある種の感作によると思われるが,胎齢の違いと母牛並びに胎児の抵抗力の差によって,脳奇形,関節彎曲症,虚弱などの病状の相違を現わすものと思考される.供試症例で見る限り,母牛を侵襲した感作の最も顕著な時期は,1972年7月中旬からの一時期と推測される. 7. 電子顕微鏡による観察で, 多くの脳グリア細胞や肝細胞中に電子密度の高い直径約100mμの粒子を所見したが,その正体は不明である. 8. 供試異常子牛からの病原微生物の分離を試みたが, 細菌, トキソプラズマ, ウイルスともに特定の病原体の分離は陰性に終わった. また異常子牛の脳脊髄液の蛋白量を測定したところ, 著明に高い数値を示すことがわかった.From the summer of 1972 to the spring of 1973, there occurred frequently among cows, abortion, premature birth, stillbirth and birth of abnormal calves having deformed limbs and/or brain, which originated in southern Kyushu to prevail in many parts of Japan, west of Kanto district. With 48 abnormal calves (Arthrogryposis-Hydranencephaly Syndrome) obtained in Miyazaki Pref., the authors conducted pathological observations and attempted separation of pathogenic microorganisms to obtain the following results. 1. The abnormal calves examined consisted of 38 beef-cattle (Japanese Black cattle breed) and 10 dairy-cattle (Friesian breed), or 26 males and 22 females as to the sex, which were born between September of 1972 and May of 1973. As for the age, they were 0-10 days old in 27 cases (including 6 stillborn fetuses), 11-30 days old in 9 cases, 31-60 days old in 4 cases, and not less than 61 days old in 8 cases, the oldest age being 252 days. 2. The abnormal calves examined could be classified into the following three types from their cacomorphosis; frail new-born calves with astasia and weakness in sucking (3 cases), calves with arthrogryposis in which limbs could not be bent nor stretched (29 cases, 6 of them complicated by hydranencephaly) and those with hydranencephaly (22 cases, 6 of them complicated by arthrogryposis). The abnormalities found with the calves born from September to December of 1972, when the prevalence of this disease started, were infirmity or arthrogryposis. Hydranencephaly appeared from January, 1973. 3. Of 29 cases of arthrogryposis in which the limbs could not be bent nor stretched, all the four limbs were abnormal in 3 cases, 3 limbs in 2 cases, 2 limbs in 16 cases (both of the forelimbs in 8 cases, both of the hindlimbs in 6 cases, 1 of the forelimbs and hindlimbs each in 1 case) and 1 limb in 8 cases. Of a total of 58 abnormal limbs, 40 limbs were stiff bent never to stretch, and 18 limbs were stiff stretched lacking in bending capacity. Thus, stiffness with bending was more frequent. Further, stiffness of limbs was complicated by spinal curvature in 10 cases. Although the muscles of diseased limbs were atrophic due to hypoplasia, generally the bones and joints showed no marked changes. 4. Brain deformities were observed in 22 cases, and complicated by arthrogyposis of limbs in 6 of them. As for the degree of brain deformities, "hydroanencephalia" in which both cerebral hemispheres were completely absent was revealed in 14 cases, and "hydro-micrencephalia" in 8 cases, in which mostly the temporal lobe of cerebrum was defective. 5. In general, the most important histopathological changes were found in the central nervous system. That is, the tissues of the remaining brain of the calves, the cerebrum of which was deficient or defective, and the brain tissues of the subjects with arthrogryposis were both observed to develop pyknomorphic and vacuolar degeneration of nerve cells consisting largely of pyramidal cells of grey matter, marked neuronophagy, neurogliosis and foci of round cells regarded as nodule of undifferentiated nerve cells. The calves born at the outset of the prevalence of this disease were observed to show a few inflammative reactions such as perivascular hemorrhage, infiltration of round cells, small hemorrhagic foci and demyelinization of anterior cornu of the spinal cord. Generally, however, changes in the central nervous system represented by degeneration were most substantial, closely resembling the pathological features of a similar disease occurred throughout western parts of Japan in 1959-'60. 6. It is considered that this disease was caused by a certain kind of sensitization attacking the fetus to affect its central nervous system. It seems, however, that the difference in the age of fetuses and also the difference in the resistance of mother cows and the fetuses resulted in the difference in the pathologies such as brain deformities, arthrogryposis or infirmity, As far as the calves examined are concerned, it is presumed that the mother cows were most markedly sensitized during a certain period of time from the middle of July, 1973. 7. In electron-microscopical observations, particles of high electron density with a diameter of ca. 10 mμ were found in many of the cerebral neuroglia cells and liver cells, the characters of which are yet to be disclosed. 8. Isolation of pathogenic micro-organisms from the abnormal calves examined was attempted to obtain negative results with specific pathogens as well as bacteria, toxoplasms, mycoplasma and viruses. Further, the quantity of protein contained in cerebrospinal fluid was determined to obtain remarkably high vale.
論文 | ランダム
- Polychlorinated Biphenyl/Biphenyl Degrading Gene Clusters in Rhodococcus sp. K37, HA99, and TA431 Are Different from Well-Known bph Gene Clusters of Rhodococci
- 従来のロストワックス法とどこが違うか--低コストCADICシステムの特徴
- 特殊合金鋼製 (冷凍用止弁・制御弁とその応用) -- (止弁及び逆止弁)
- 鋳型用添加材の繰り返し使用による挙動 (鋳物砂特集号)
- 鋳物砂部会から (鋳物砂特集号)