抄録
In order to study affecting factors on development of the paralysis in polio patients, feces were collected from six paralytic polio patients and four inapparent infection cases for the virus infection. Ten strains of poliovirus type 2 were isolated from these specimens, and the difference of these strains were compared with each other in the respects of plaque size of the strains, neuroviruleuce to mice when the strains were intraspinally inoculated into mice, and the quantity of poliovirus excreted in those feces, which were indicating respectively the multiplication efficiency, the neurovirulence, and the extent of virus growth in intestinal tract of those polioviruses.
The results were as follows:
1) The quantity of poliovirus excreted in feces: The quantitative difference did not depend upon the day of illness when the materials were taken and also clinical types of infections: paralytic forms or inapparent infections.
2) The measurment of plaque size of the strains: Plaque size of the strains of poliovirus type 2 from the inapparent infections were 5.19±0.37-1.75±0.11(mm), and. that of the paralytic forms were 5.29±0.36-1.66±0.10(mm). These clinical forms did not differ in their range of variation.
3) The neuroviruleuce to mice when the strains were intraspinally inoculated into mice: When these viral strains were intraspinally inoculated into mice, there was significant difference between two groups of mice; one group which received viral strains from paralytic polio showed 23.4per cent of mortolity and the other group which was inoculated with viral strains from inapparent infections displayed only 4.3per cent of mortality. The difference can be conciderd significant.
From these results mentioned above neurovirulence may play the most important role to convert a poliovirus infection to clinically manifest paralytic form.
