GROWTH OF MEASLES VIRUS IN NERVOUS TISSUES

1. NEUROTROPIC PROPERTIES OF MEASLES VIRUS IN NEWBORN HAMSTERS

Abstract

Nine strains of measles virus of different origins and passage histories were examined for their neuropathic properties in newborn hamsters and mice. The TYCSA strain, a clone variant of Toyoshima strain, was the highest in neurovirulence, and unattenuated Edmonston strain was found also to be highly neurovirulent. Unattenuated Tanabe strain and two wild strains failed to produce the illness in either animal species. Among the four attenuated vaccine strains, Tanabe-CAM and Schwarz strains were relatively of high neurovirulence on primary inoculation, but Leningrad-16 and Sugiyama strains were very low in virulence. With one of the low virulent strains, Leningrad-16, a limited growth occurred in the brain tissues of newborn hamsters after intracerebral inoculation, but no antibody response was detected in the survived animals. Increased resistance to the infection with the neurovirulent TYCSA strain was observed in the suckling hamsters of 7 or more days of age. Treating with anti-measles serum before infection was found to protect the newborn hamsters from the lethal effect of the neurovirulent strain.
As a model of human measles encephalitis, pathogenicity of the neurovirulent strain in producing encephalitis in newborn hamsters was discussed.