THE HISTOLOGICAL diagnosis of rabies encephalitis relies in great part on the demonstration of cytoplasmic inclusions, among which the Negri body is considered pathognomonic for this disease. In laboratory animals, however, Negri bodies are identified only in animals inoculated with the street strain virus1 and are not seen following inoculation with the fixed strain. Regardless of the presence or absence of Negri bodies, virus particles can be reisolated and morphologically identified in the electron microscope in all inoculated animals.1-5 This inconstant appearance of the Negri bodies has led to the hypothesis that these structures may represent products of cell reaction to virus rather than actual sites of virus replication. In the following report are presented findings in a human case, and based on examination of alternating thin and thick sections of material embedded in epoxy resin, the ultrastructural equivalents of the varied cytoplasmic inclusions are illustrated.
Morecki R, Zimmerman HM. Human Rabies Encephalitis: Fine Structure Study of Cytoplasmic Inclusions. Arch Neurol. 1969;20(6):599–604. doi:10.1001/archneur.1969.00480120045003
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