The Echigo-1: a panencephalopathic strain of Creutzfeldt-Jakob disease: a passage to hamsters and ultrastructural studies.

The Echigo-1 strain of Creutzfeldt-Jakob disease (CJD) was isolated by Mori and colleagues (1989) from a case of a 33-year-old female with a panencephalopathic type of CJD. We report here ultrastructural data on the first passage in this laboratory. The bulk of the lesions was localized to the brain stem and cervical cord. Neuropathology was extraordinarily florid but quantitatively not much different from that reported for other panencephalopathic model of CJD, the Fujisaki (Fakuoka-1) strain of CJD passaged in NIH Swiss mice. Two types of vacuoles were easy to discriminate: typical change and intramyelin vacuole which are encountered in otherwise typical polioencephalopathic models but in much lower number. Some axons underwent Wallerian degeneration, others met criteria of dystrophic neurites and both alteration existed in the same areas. In neurons, nuclear paracrystalline rod-like inclusions were visible; other inclusions comprised spiroplasma-like inclusions in synaptic boutons. Robust cellular reaction comprised of reactive astrocytes and macrophages filled with cellular debris.