Ultrastructure of the Negri body in human rabies

Abstract The inclusion bodies found in 4 cases of human rabies encephalitis, necropsied at short intervals after death, were studied by electron microscopy. One of the typical appearances was similar to that of the Negri bodies seen in experimental virus infection and showed at the periphery large matrix aggregates with typical forms of the virus enclosed in profiles of the endoplasmic reticulum. Another typical structure was made up of tubular structures with open ends immersed in the matrix. Typical virus forms were rarely found at the periphery and no transitional forms between them and the tubular structures were encountered. This second type of Negri body was thought to represent foci of less active virus replication.