Pathological studies on an acute hemorrhagic disease in pastured cattle in Tottori Prefecture. Cases occurring in 1967

Abstract

In recent years, a disease which is called panmyelopathia, bracken poisoning, or fernpoisoning has occurred and come into question among pastured cattle in various districtsof Japan. The authors have encountered some cases of the disease taking an acute fatalcourse among pastured cattle in Tottori Prefecture since 1967. This article deals witltcases which occurred in September, 1967, and were examined pathologically.The materials used for the present investigation consisted of 9 Holstein cattleranging from 8 months to 5 years of age and suffering from this disease on two improvedpasture-grounds located at the foot of Mt. Daisen. Clinically, the affected cattle had atemperature of 4l.5C and a tendency to die with multiple petechiae on the mucosa ofthe nasal cavities, oral cavity, anus and vagina in one week after falling ill. In some ofthe cattle examined, the white and red blood cell counts were less than 4, 000 and lessthan 3, 600, COO per mm3, respectively.Pathologically, general circulatory disturbances, such as nnultiple hemorrhage andedema, were first noticed. As morphological alterations which seemed to be closelyrelated to these lesions, swelling, loosening and hyalinization of the walls of blood vesselsand thrombosis were frequently pointed out. Furthermore, the thrombosis was regardedas being connected with the formation of erosions and ulcers observed in the mucotusmembranes of the nasal cavities and of the digestive canal.Secondly, the bone marrow was replaced by fatty marrow, which was associated withan increase of plasma cells and which showed no hematopoietic activity. Plasma cellsincreased in number also in the medullary cords of the Nymph nodes and splenic sinuses, as well as in the bone marrow. Furthermore, plasma cells, as associated with fibroblasts, were frequently observed in edematous connective tissues.In addition, focal hepatic necrosis, fibrinous pneumonia, and peritonitis were Ire-quently recognized. No regressive changes were present in the Iymphoid tissues. Apart from the cause of this disease encountered, many of the pathological findingsobtained were analogous to those described in the poisonous disease mentioned above.In this study, however, the appearance and increase of plasma cells were noticed invarious tissues. Then, the alteration of the walls of blood vessels and the formation ofthrombi played an important role in the histopathogenesis of hemorrhage and edema Nutthe disease encountered.