In search of the enteroviruses in cattle from Kumamoto, nine isolates cytopathic for bovine kidney cells were recovered from fecal specimens. Judging from their cytopathic effect, small size, resistance to ether, RNA type, and other properties, they were presumed to belong to the ECBO virus group. Serologically, they were classified into three distinct types, which were tentatively designated as Types 1, 2, and 3. Type 1 was closely related to BF1 described by Inaba et al., but the others were not.
The isolates were passed consecutively in various cell lines, such as BK, chick-embryo fibroblasts, HeLa, Ps, and TC cells yielding cytopathic changes. The progeny began to appear in 6-24 hours. The infective titer reached its maximum in 24-96 hours after inoculation. Hemagglutinin was produced parallel with the growth curve. It is interesting to note that hemagglutinin production varied according to strain, type of cell, and passage.
A total of 709 serum samples from cattle, horses, swine, goats, dogs, and human beings were then tested for neutralizing antibodies.All of them, except those from dogs, had the antibodies against Types 1, 2, and 3 with thefollowing frequencies: 56.0, 17.7, and 42.5 for cattle, 37.5, 6.3, and 0 for horses, 59.7, 70.3, and 30.0 for swine, 25.5, 22.5, and 0 for goats, and 78.5, 94.3, and 0 for human beings, respectively. This finding strongly suggests that the infections of the three type ofviruses are widely spread not only among cattle but other species of animals. and human beings.
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