Selection of avirulent variants of Rift Valley fever virus
Koyama, H.; Higashihara, M.
Kitasato Archives of Experimental Medicine 47(4): 67-76
1974
ISSN/ISBN: 0023-1924 PMID: 4465474 Document Number: 76845
By plaque-cloning of the pantropic strain of Rift Valley fever virus, some variants differing in virulence for adult mice were selected. The D2 variant showed a virulence profile very similar to the parent virus when injected intraperitoneally or intracerebrally. However, its virulent effect after intravenous injection differed slightly from that of the parent; 60% of animals showed nervous symptoms and died 8-11 days after the injection. The E-clone variants, E1, E3 and E4, were avirulent when injected intraperitoneally or intravenously. Neither virus in the liver nor viraemia could be detected in the animals injected with these variants. In the case of intracerebral injection, approximately 70-90% of animals exhibited nervous symptoms and died 4-12 days after the injection.