豚における肺吸虫症(Paragonimus Westermanii自然感染)の病理組織学的研究(獸医學)

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Miyazaki discovered a new species of Paragonimus ohirai Miyazaki in 1939. He made it clear that P. westermanii (Kerbert, 1879) was not only lung-fluke to be found iti Japan, contaray to the then accepted theory. In 1945 he found a morphologically different metacercaria from that of P. ohirai. He succeeded in obtaining an adult worm of that metacercaria following an artificial infection in a test animal. Since he could not morphologically differentiate the adult worm thus obtained from that of P. ohirai he tentatively named it as "Small type of P. ohirai". He made a comparative study on the worm with those specimens sent by Chen. Their opinions wereexchanged, resulting in a conclusion that the worm in question was nothing but P. iloktsuenensis Chen, 1940. Miyazaki's studies have proved that there are 3 species, i. e. P. westermanii, P. ohirai, and P. iloktsuenensis, in Japan. Thus in Japan the identification of lung-fluke in men, domestic animals, and in wild animals has become a matter of great consideration. Recently at Osaka-City Slaughter House the authors had an occasion to examine an immature adult of lung-fluke in hog lung as well as liver, in an effort to give a careful identification of the species. Formerly the researchers found it very difficult to differentiate species of lung-fluke by their adult worms. From various metacercariae Miyazaki has experimentally obtained respective adult worms, and made a comparative study which has enabled him to give an easy differentiation among some species. Bifurcation of the ovary, growth of cuticular spines, the rate in size of ovary and testis, and the characteristics of egg have been minutely scrutinized. Especially the former two characters have been greatly stressed upon. After Miyazaki's classification the authors' study has revealed that the present specimens are identified as P. westermanii. So far many histopathological reports have been made on worm cysts of lung-flukes in men, dogs, and cats (in most cases done with experimental animals) in Japan with some detailed findings. But swine cases do not seem to have been histologically reported in detail except for macroscopical study of Kawamura (1917), Tokishige (1918), and Oishi and Saito (1952). The authors studied the present challenging case with a careful histological survey of the infected viscera. The results obtained are as follows: (1) After Miyazaki's classification, the lung-fluke found in about one year old hog (Osaka-City Slaughter House raised in the Kyushu district) has revealed to be P. westermanii. (2) A single worm is found in the cavity of worm cyst in lung and liver. (3) The worms obtained from lung and liver have grown to Ando's "immature adult or third stage". No formation of vitellarium is observed. (4) So far as the present case indicates, P. westermami has a hepatotropic characteristic. (5) The worm cyst in the lung locates in the parenchyma subpleurally. It is nodulously elevated and is round shaped with its cut surface almost round. The worm cyst in the liver locates subcapsularly. It is elevated button-like on the surface, and is in shape of ellipse with its cut section elliptic. (6) The worm cyst in the lung forms a cavity of softening cyst. It shows no signs of bronchiectasis (fig. 4). (7) The wall of worm cyst is composed of granulation tissues where marked cell infiltration is demonstrated by predominant eosinophils. This finding corresponds to Kobori's "granulation period". But the tissues on the wall do not necessarilly show a common finding with the rest of the tissues. A finding of "infiltration period" or "organization period" is observed in some areas (fig. 7, 8, 9). (8) The worm cysts of lung and liver show an appearance of epitheloid cells on their innermost layers. (9) Main changes found in the pulmonary tissues around the cyst worm are catarrhal pneumonia, hemorrhagic pneumonia, fibrinous pneumonia, productive pneumonia, bronchitis, peribronchitis, bronchiectasis, rupture of bronchial wall, hemangiectasis, aneurysm, varix, perivascular cellular infiltration, rupture of blood vessel, hamorrhagic remains, scarred nodule, localized induration, and villous pleurisy. (10) In the stroma adjacent to the pleural lesion and worm cyst, a scarred nodule is odserved which supports to consider that the worm invaded pleura, stroma, and then parenchyma in order. (11) No mast-cells are detected in the present inflammatory lesions. (12) On the scarred nodule there appear "large mononuclear orange-granulocytes" (tentatively named) bearing orange color granules (fig. 12). A small group of "large mononuclear eosinophils" (presumably eosinophilic myelocytes) is found in the cirrhotic lesion around the nodule and in the proliferated interstitial connective tissues of the liver, with marked round cell infiltration (fig. 13). (13) The pulmonary lesion demonstrates a small focal infiltration of mononuclear eosinophils as well as of typical eosinophils. (14) Proliferation or regeneration of fine smooth muscle fibers is observed in groups in the wall and surrounding tissues of the worm cyst as well as in the surrounding tissues of the scarred nodule (fig. 10). (15) Fine Charcot-Leyden crystals are demonstrated in the worm cavity of lung where fine eosinophils are collected. They are especially found in a group of degenerated or necrotic eosinophils (fig. 6). (16) Hilar lymphnode findings are focal infiltration of neutrophils in cell-poor substance (small abscess formation), diffuse eosinophils infiltration, and localized atrophy of lymphoid tissues where the cell-poor substance is found proliferated. These findings are closely related with pulmonary changes (fig. 5).
大阪府立大学の論文
1954-02-25

豚における肺吸虫症(Paragonimus Westermanii自然感染)の病理組織学的研究(獸医學)

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