الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
RVF is an infectious disease. The best mean to control the disease was vaccination and eradication of vector. Many vaccines were used for this purpose , one of them it was mutagen variant using 5 - flurouracil on tissue culture. In this study trials were conducted to prepare attenuated RVFV using 5 - flurouracil.
Firstly , titration of original RVF strain was conducted on BHK and CER cell line , the titer was 7.5 and 7.8 Log,. =Ds. / 0.1 ml respectively also titration using adult mice resulting in titer of 106’ MIPLID„D / 0.1 ml. The safe concentration of S - flurouracil on BHK cell and in adult mice were 100 - 300 ug ml , but concentration over 300 ug / ml were toxic for both tissue culture and adult mice. The effect of 5 - flurouracil on RVFV was studied using passages in adult mice after treatment with different concentration of 5 - flurouracil ( 100 , 200 and 300 ug / ml ) virus titer in adult mice and pathogenicity in baby mice were conducted to every serial passages. The titer was decreased from 10’ MIPLDso / 0.1m1 to under one log,. MIPLDso / 0.1 ml after using 300 ug / ml concentration of S - flurouracil. The pathogenicity of this passage was lowered as the adult mice inoculated with it were survived for 3 weeks after inoculation , but it caused 70% deaths among baby mice. This passaged virus was adapted for two passages on MK cells and was titrated using suckling mice , its titer was 7.4 and 7.3 Logi, MICLDso / 0.02 ml. This adapted virus ( MP,, ) was tested by further 7 passages in suckling mice without addition of 5 - flurouracil with MPi, and titrated. The titer was ranged from 7.0 to 7.2 Logi° MICLD50 / 0.02 ml. MPi, was exposed to potency test by inoculating adult mice resulting in 90 - 100 9 protection. MPi, virus was evaluated in pregnant mice. It was not abortogenic and the delivered baby mice were normal and healthy. Further evaluation was conducted in adult sheep by inoculation of one group ( 4 sheep ) with 1 dose ( 1 ml of 104 MICLD„, / 0.02 ml MP,;? virus ) and other group ( 4 sheep ) with 5 doses of to same titer of MP,, virus. Seroconversion studies were studied using SNT and ELISA tests. After one month these animals as well as control animals were challenged with virulent RVFV. Vaccinated animals with MP,, did not show any reaction post challenge with virulent RVFV.