Abstract
As has already been reported, endemic goiter is prevalent among farm animalsin Nagano prefecture. The correlation of disease of farm animals and human beingswith rats seemes to be closed. In the present study, on the basis of these findings, histopathological observations were made on the thyroid glands of rats obtained inNagano prefecture. Moreover, the results were compared with the findings on thoseexamined in Toyama prefecture. Eleven rats (7?. rattus) and 4 mice (Mus molos-sinus) from Nagano prefecture, and 17 rats (R. rattus) and one mouse (Musmolossinus) obtained in Toyama, were used for this purpose as materials.The glands are classified by the characteristic features of acini, and the mainresults are summerized as follows :Type 1 (normal gland) : The follicicles are fairly uniform in size (30 to 50micron in diameter) and lined by uniform, low cuboidal cells. Twelve glands of thistype (66.7 per cent) were obtained in Toyama prefecture and 9 (60.0 per cent) inNagano.Type 2 (so-called "the thyroid gland in regions of endemic goiter") (almostnormalType 4 (glands present a solid mass made up of small follicles) : The acinarcavity are narrowed into a rectangular form with deeply stained nuclei. The cot-loid is abundant or pale. One case (5.5 per cent) was found in Toyama prefecture, and 2 cases (13.3 per cent) in Nagano.Type 5 (parenchymatous goiter) : The follicular epithelium varies from alow cuboidal to a high colmnar. The parenchyma cells increase in number tilltheyfrom a papillary proliferation in the acinar cavity. They are usually irregular inshape, and these nuclei are oval or spherical. The acini average from 45 to 105microns in diameter. The colloid is small or absent. Type 5 was one (6.7 per cent)of the 15 cases in Nagano prefecture.The result of this examination may be noteworthy. In place of the suspended cell culture method used bv most investizators in therast, ENDERS and his co-workers r>lasma-clot culture-method was used. Using thesvnthetic medium No. 199, containinz horse serum, roller tube culture of spleenand kidney tissues were undertaken.Hog cholera virus was first injected into and then cultivated in the tissue cultureand then transfered into another one. Tissue culture of the lVIiyazaki strain of 9rassaues and the ALD strain of 4 rassazes were infected into the swine. On the12th passage of the lVIiyazaki strain, infective fiter was also determined.From the results of clinical findings, percentage of leucocytes, anatomical viewsand bacteriological examination, it was confirmed that the pathogen which producedthe disease in all the pigs tested and which caused their deaths, was hog choleravirus descended from the one used for inoculation. The infective fiter was a dilu-lion of 10 It stood 10 days in Miyazaki strain and 17 days in ALD strain asa course of disease. This fact seemed strange, because it is characteristic that thecourse of the disease is longer in the Miyazaki strain than in the ALD strain whenfresh, natural blood virus is injected. If the prolongation of the course in the ALD strain means the decrease of virulence, it may be considered that the Miyazakistrain is more suitable to the tissue culture than the ALD strain. In the groupof dilution 10- in the infeetive Liter test, febrile reaction appeared normal betweenthe 8th to 17th day of the disease and was supposed to recover and resist, but itwas followed by a secondary rising of fever and death on the 34 th to 37 th dayof the disease.It was uncertain whether the fact was caused as a result of the chronic course9of the disease owing to a dilute virus or whether it was caused by other, secondaryreasons. But, the characteristic changes indused by chronic hog cholera wererecognized. on autopsy, and the bacteriological examination was negative. Fromthese facts it was considered that the death was caused by hog cholera virus. [the rest omitted]
