ABSTRACT
<p><b>BACKGROUND</b>To observe cytopathogenic effect of Hantaan virus (HV) on cultured human bone marrow cells.</p><p><b>METHODS</b>Light and transmission electron microscopy and direct immunofluorescent technique were applied to study cellular structure especially ultrastructural changes of bone marrow cells from patients with Hantaan virus infection. Bone marrow cells of one healthy volunteer were also studied as control.</p><p><b>RESULTS</b>The antigen of HV was found in bone marrow cells of 20 of 27 HFRS patients by the aid of direct immunofluorescent technique. It was found that the granulocytes had the highest percentage of HV antigen positive cells (76%), followed by monocytes (65%), lymphocytes (40%), megakaryocytes (20%) and the lowest was found in erythrocytes (3.7%). The injury of cell membrane after infection with HV was significantly more severe than that in the control group under the light and electron microscopy.</p><p><b>CONCLUSION</b>This study demonstrated that HV could attack human bone marrow cells and cause cytopathogenic effect on them.</p>