Histopathologic changes of the spleen in suckling rats inoculated with Hantaan virus

The purpose of this study is to delineate the histopathologic findings of the spleen after Hantaan viral inoculation, which is the largest lymphoid organ in rats, and to identify the viral location by anti-Hantaan virus (HTNV) monoclonal antibody. All the sixty one suckling rats of less than twenty four hours of age were used. Except twenty one rats of control group, twenty-five rats inoculated intracerebrally for the early change and fifteen suckling rats inoculated intramuscularly for the late change were uniformly susceptible to lethal infection with the ROK 84-105-1 strain of seed HTNV. The characteristic histopathologic findings were; appearance of macrophages below the splenic capsule on the 3rd day, small lymphocytes around the periarteriolar sheath on the 5th day increasing in numbers on the 7th day, and a markedly expanded marginal zone with some immunoblasts and plasma cells as well as decreased extramedullary hematopoiesis on the 9th and 14th days. Time of onset of histopathologic changes in spleen thickness, appearance of medium and large lymphocytes and degree of extramedullary hematopoiesis were influenced by inoculation route, whereas expansion of the marginal zone was affected by postnatal age.

Epidemic Hemorrhagic Fever in Korea

Korean Hemorrhagic Fever was recognized during the Korean War (1950-1953) and intensive studies have been done especially in early 1950's. However, the etiologic agent, vector, and reservoir are not known conclusively. The occurrence has two peak seasons in spring and autumn, and is not limited to military personnel in front lines but also civilians are attacked. Still the study is going on.

Light and Electron Microscopic Studies of Megakaryocytes in Korean Epidemic Hemorrhagic Fever

Light and electron microscopic studies of megakaryocytes in bone marrow from 14 cases of Korean epidemic hemorrhagic fever were made, together with clinical manifestations, laboratory findings, and changes in other marrow elements. The number of megakaryocytes increased in various degree from patient to patient, with a shift to the left of maturation gradation. Cytoplasms were markedly smaller but granularity was fairly good. The most constant finding was marked decrease or complete absence of platelet formation at the periphery of the cytoplasm. Ultrastructurally, there was a marked decrease of the cisternal system in the cytoplasm and lack of cleavage line. No virus particles or active degenerative process was noted. These changes of the megakaryocytes are similar to those reported in idiopathic thrombocytopenic purpura, indicating that megakaryocytic changes in Korean epidemic hemorrhagic fever are likely secondary to thrombocytopenia which was caused by other Mechanism.