Sagiyama Virus

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Abstract
Summary Sagiyama virus produced disease in suckling mice 2 to 12 days after intracranial inoculation, and in chicken embryos 2 to 8 days after yolk sac or chorio-allantoic membrane inoculation. Histopathology in suckling mice resembled that of group B Coxsackie viruses; focal myositis, neuronal degeneration in spinal cord and brain, and brown fat necrosis occurred. Deaths were irregular in baby chicks, but viremia commonly occurred. Weaned mice, rabbits, guinea pigs, and swine produced antibodies, but showed no disease. Porcine and hamster kidney cells in primary culture were destroyed by Sagiyama virus, and small plaques occured with chicken embryonic cells under agar-containing medium. Cell destruction was not seen in chicken embryonic cells with fluid medium, nor in primary cultures of monkey or calf kidney or human amnion, in L mouse fibroblasts, or in 8 human epithelial cell strains maintained in continuous culture. Sagiyama virus, like other arthropod-borne viruses, was inactivated by sodium deoxycholate and ethyl ether. Its size estimated by Millipore filtration was larger than the 15 to 30 mµ size of Japanese encephalitis virus. Acetone-sucrose extraction of infected brains from suckling mice yielded potent CF antigens and agglutinins for baby chick and adult goose erythrocytes. Embden goose erythrocytes were agglutinated in slightly higher titers than Toulouse goose cells. The optimum pH for hemagglutination was 6.2 to 6.4, but no difference was found between 25° and 37°C. Some strains of virus produced potent hemagglutinins by the acetone-sucrose and protamine precipitation method, whereas others failed to yield potent antigens even though their incubation periods and passage levels in mice were similar. Supernatant fluids (104 G, 60 minutes, 5°C) of saline suspensions of infected brains also were useful as complement-fixing antigens, but similar supernatants of borate-KCl brain suspensions at pH 9 or acetone-ether extracts of brain did not agglutinate chick erythrocytes. Hemagglutination-inhibiting antibody titers were equal or 2- to 4-fold higher with agglutinins from the Japanese prototype strain, M6/Mag 132, than with an agglutinin from the closely related Malayan virus, MM 2021. Neutralizing, hemagglutination-inhibiting and complement-fixing antibodies were produced in mice, rabbits, and guinea pigs; in swine, one virus strain in first mouse passage from mosquitoes engendered all three antibodies, but another strain in thirteenth passage stimulated only a neutralizing antibody response.
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