The ultrastructurai changes ot the cerebral cortex oi suckling mouse brain inl-ected with HFRS virus by intracerebral inoculation and the morphogenesis of HF-RS virus were studied by IBM. The results showed that the nerve cell

neuroglia cell and endothelium cell of the capillary in cerebral cortex were all able to be infected with the virus. Varying degrees of ultrastructurai changes of the infected cell occured and became serious in the process of infection.virons in different stages of assembly and viral precursor labeled with HRP were found in cytoplasma. Most of the virons were spherical or oval with mean diameter 97 nm

and a few of them were rod-like. The virus had a granulofibrilla inner component with an envelope around it

some had an apparent electron-dense coro. Virus matured by budding from the membrane of vesicle or ER labeled with HRP. Many inclusion bodies or some masses of numerous 40-50nm spherical vesicle-like particals labeled with HRP were found in cytoplasma

and a kind of electron-densa material labeled with HRP was occasionally observed beneath the plasma membrane

of which the precise association with the virus wasn’t known