RusV RNA was detect by RNAscope in situ hybridization ( a d ), while RusV capsid protein was detected by immunohistochemistry ( e h ). Detection of rustrela virus (RusV) RNA by RNAscope in situ hybridization ( a d ) and RusV antigen by immunohistochemistry ( e h ) in the central nervous system of encephalitic cats. Both virus RNA and capsid protein were located mainly in the cytoplasm of different nerve cell populations. Typical are spherical reaction products, which may coalesce to more extensive and/or diffuse signal. Neurons with the highest viral load were particularly Purkinje cells ( a , e : PC), granule cells of dentate gyrus ( b , f : GLD), pyramidal cells across cerebral cortices including neocortex ( c , g : Py). Also, numerous RusV-positive cells are seen in lower brain stem and spinal ventral horn neurons ( d , h : VHN). GLC: granule cell layer of cerebellar cortex; GLD: granule cell layer of dentate gyrus; NCR: neocortical ribbon; PC: Purkinje cell; Py: pyramidal cell; VHN: ventral horn neuron. Cats: a , e SWE_03; b , f SWE_11; c , g SWE_05; d , h AUT_09. Representative images of RusV-infected cats are presented. All case and control cats ( n = 29 each) were analysed. Results of IHC and ISH analyses are presented in Table 1 and Fig. 2 .
