| Summary |
The ultrastructural changes in the central nervous system of pigs were studiei a&r intanasal infection with 1G’1.6 TCIDSO TilL strain of psewiorabies virus. Only mild swelling of mitcchondria was found at 1 day pcrstincculation (DPI), Many unenveloperl virus particles with oval or icosahethal capsids were found in the axoplasm from 2 to? DPL The diameters of unenveloped virus particles and oore were co-i 10 and 20-80 nra, respattively. The cytopathologic changes found in affected neurons were descriLed as darease or disappearance of endoplasmic reticulum, formation of various siJ
vacuoles and polymerition of neurofilaments in the cytoplasm, and dilatation of nuclear envelope and it pores. Degeneration of axon and demyelination were also found at the same time. From 3 to 5 DPI, proliferation of microglias, phagccytosis by the maaophages, lympliccytic perivascular cuffing and other cytopathologic changes of neurons were more promenent. These lesions lmme most severe at 6 and? DPI, but could not It found afrr 14 DPI. No vasculitis was sn in the central nervous system. It was strongly suggesI that the spread of pseudorabies virus in the central nervous system might not through hematogenous route
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