Japanese Journal of Veterinary Research;Volume 9, Number 2



SATOH, Hiroshi

Permalink : http://hdl.handle.net/2115/1746
JaLCDOI : 10.14943/jjvr.9.2.41


Detailed neuro-histopathological investigations were performed, being grounded on the general point of view, on thirty-one naturally occurring cases gathered during the years 1948 to 1957,of a swine disease in Janan, so-called "encephalitis eosinophilica suis." The cardinal symptoms of it consist of circular movement, convulsions, epileptiform seizures, etc. Histopathological lesions of the disease in the central nervous system are chracterized by various processes consisting of nerve cells diffusely extending over all areas of the brain and spinal cord, mainly pseudolaminar focal necroses (pallidness or focal pallor to malacia) principally being located in the grey matter of the prosencephalon especially in the cerebral cortex and perivascular and tissue infiltration of eosinophil leucocytes principally observed in the cortex and meninges of the telencephalon. The focal necroses, furthermore, are occasionally located in the grey matter such as in the cerebral nuclei, diencephalon, mesencephalon and medulla oblongata. Histo-pathogenetically, a great importance is attached to the fact that most basic pathological processes in the central nervous system of the disease may possibly have much connection with a certain toxic condition originating from systemic metabolic disturbances of fat substances of certain kinds. Such disturbances were proved by the degenerative condition of nerve cells (acute cell change), metamorphosis of fat tissues belonging to the category of changes of "yellow fat disease, " degeneration in the parenchymatous organs and deposition of acid-fast pigment substances detected in the central nervous system, etc. It was confirmed that the necrotic-desolated processes of the central nervous system offer much evidence that they had origin in local functional disturbances of the blood circulation (SPIELMYER); such changes were regarded as secondary ones. There is no wholly denying the surmise that the acid-fast pigment substances which were regarded as an abnormal product of metabolism of fat substances of a certain kind may take part in the functional disturbances. It is conceivable, in conformity with histological findings, that these acid-fast substances may have various chemical states ranging morphologically from non-phanerous to phanerous, the latter showing acid-fastness for the most part. With the exception of reparative symptomatic inflammatory infiltration into the necrotic-desolated processes, as to eosinophil cell infiltration which was recognized in almost all the cases, the author would like to comprehend it as likely manifestation of the function of the cells which acceleratedly act to counteract to the abnormal pigment substances ; in other words, such infiltration is a phenomenon which belongs to a simple reactive process of the body. With the exception of glio-mesenchymal reactive process to the necroticdesolated lesions, mesenchymal changes consisting of swelling, increase, etc. of cells of the walls of the blood vessels, being observed particularly in the grey matter and meninges of the prosencephalon, were regarded as changes reactive to the disorder of the tissue and the abnormal metabolic substances. Edematous focal tissue loosening of various degrees observed frequently in the cerebral cortex are considered to be a secondary process having to do with hyperemia and fibrin thromboses of the blood vessels principally of the veins. As to the causal genesis of the present disease, "yellow fat disease" of various creatures and encephalomalacia of chicks are referred to as interesting objects from the morphological standpoint. A certain swine disease in Europe and America, having a name similar to that of the present disease, is clinically and morphologically similar, if not identical, to the present disease.