Morphological differences in the central nervous system and organs of monkeys inoculated intracerebrally with virulent and attenuated strains of mumps virus.

The degree of attenuation of mumps virus was studied in intracerebrally inoculated Macaca mulatta monkeys. The virulent Leningrad-3 strain and its attenuated variant as well as the attenuated Sophia-6 strain were used. The nature of pathological alterations in the neurons pointed to neurotropism of only the virulent strain. Morphological changes caused by attenuated and virulent strains in the brain structures, in the epithelium and glandular structures of the salivary glands differed considerably and may be used as a kind of markers of neurovirulence and the degree of attenuation of mumps virus strains.